[Herr Brackhaus]

Wireless Weapon + RFID Sensor Tag with either a Motion Sensor or a Milimeter Wave (aka Cyberware) Scanner; hook the former up to the latter, and make it fire a fraction of a second after movement is detected.

Or, use some of the security features in the books; pressure pads, trip beams, proximity wire, or a good old fashioned security camera linked to the weapon with a pre-programmed setting for when to fire it.

[DigitalZombie]

Im no IED expert, but heres some suggestions anyway

LMC (low metal content, difficult to find with a minesweeper, made of fertilizers and stuff, popular in Afghanistan)
IR often used in conjunction with the EFP Namikaze mentioned
RC (radio controlled, easily handled with hackers or jammers)  except Im not sure that you can by RAW jam a wireless signal in SR5 universe
Timed (TB liked to used timed rockets to attack bases/cities etc. they just placed the triggers inside a water filled clay jug, and when the sun had evaporated enough og the water the 2 contacts would be clode enough to trigger an ignition of the rocket that would inshallah go in the right direction)
PR (pressure release, the opposite of IEDS that are triggered when pressure is applied by, say a boot) while this one isnt especially brilliant or anything it would make for a great scene involving the players. Imagine the hacker disabling "all" the explosive devices from the matrix only to find out that he just stepped on an IED, and he has intel on that stepping away from the IED would trigger it. The team now has to disable it while he stands on it or alternatively do an "Indiana Jones move" and replace said hacker with another heavy object.

more shadowrun related
facial/voice/vehicle signature/etc recognition software (either blows up specific persons, or set to not blow up specific persons. Could alternatively be made to recognise symbols or objects like silver skulls of the Nosferatu coven of big bad evil guys foundation.)
alchemical preparations in conjunction  with an explosive charge, Im not sure but I suppose street magic has a more indepth use of preparations.
2 compound explosive components -  do some runs:  implant non-lethal components into the latest Hurgl! rockstar juice and Mental mentos super popperz candy. When in contact with each other and an acid (like stomach acid) the components would cause a lethal internal combustion (or a large belch for the body 11 troll).

[The Wyrm Ouroboros]

If you're going to have gecko-tape on a grenade, don't set up to bounce up.  Set it to drop down.  You activate the thing with a delay - 10s, 30s, whatever - and toss it upwards onto the ceiling - because pretty much nobody looks up.  When it receives the motion sensor indicator to activate, it doesn't need to bounce up - it just lets go, and a quarter of a second later (9.8m * 0.25² = roughly 0.61m out of a 2.5m hallway = 1.88m detonation height) it goes off.  Pretty much right at head height, too.  If you want it a bit lower on the same height ceiling (2.5m = 8' 1.5") - say, 1.3m, get the dwarves in the face while everyone else gets it in the gut - then make it a third of a second delay between release and detonation.  And if you're feeling REALLY ugly, make it re-engage the gecko-grip tape a tenth of a second after letting go (when it gets just a bit of distance), so that if some damn fool manages to react and grab it, he then has a grenade stuck to his hand.

... no, actually, I haven't thought about this.

[Namikaze]

Now there's a twisted and horrible trap to throw at people!

[The Wyrm Ouroboros]

Other simple traps are good - but a lot of this other stuff can't be just done on the spot.  It requires preparation.  And usually it requires a 'kill-house'.

• Balsa-wood covering up a bed of rusty nails; step on it, your feet go through, and you get a rusty nail in you.  Got armor on your foot - or your tetanus up to date?
• So-called 'reaper' traps, steel bars with heavy springs to snap them out (across, or even straight out - especially if it's sharp) of a wall when a UV laser or other tripwire goes 'ping', doing some serious damage at X height.
• An apparent grenade-under-a-board trap (you know, remove pin, use loose board to hold down spoon, someone moves the board the spoon goes 'ping' and the grenade goes 'boom') but when a person goes to one or two of the best places to disarm it, THOSE are the place(s) that are trapped.
• Claymores in the walls with tripwires all over the place - but only one of them (or a UV laser tripwire, or a weighted floor trap) trips the detonation sequence, which starts at either end and cascades towards the middle.
• Floor traps on two or three stairs in the entire flight, which pops grenades from up top down into the stairwell.
• For survivors of the above, same thing - but the floor traps are more obvious.  The real trap is when a certain amount of weight is on the entire flight, and then grenades drop.  Even worse, FAKE grenades drop, causing everyone to pack into the hallway down below - and then the claymores in the walls (on a delayed trigger for when all or most of the weight is back OFF the stairs) go off.
• For the tough trolls, a column of rooms which, when you see them enter the one on the top floor, you can trigger to blow the floors.  ALL the floors.  "Yeah, yeah - can your legs survive a five-story drop onto a busted-up uneven and sometimes jagged concrete surface?'
• If you're in a taller building, a la skyscraper, set the room to blow three sides - make a ramp out of it.  Just make sure the slide goes out the window.  Five stories, sure, but thirty?

Really, get inventive.  You have technology, various sorts of triggers, and a building.  Limitless imagination.

[Namikaze]

If you're in a taller building, a la skyscraper, set the room to blow three sides - make a ramp out of it.  Just make sure the slide goes out the window.  Five stories, sure, but thirty?

This is just messed up!

[The Wyrm Ouroboros]

Clearly you need to watch more movies.  Gwen Stacy, Spiderman 3 - sliding out of an office building.

[The Wyrm Ouroboros]

Hm.  Fred Perry is releasing issues 1-199 of Gold Digger for free, which reminded me of the ever-lovin' Peebos, which made me wonder ... did 4e have gecko-tape wheels for vehicles, even small ones?  Hm.  Well, the microdrones might have the stuff on their feet; the waspy drone does, doesn't it?  A microdrone with a single-shot short-range grenade launcher, or even just the capacity to carry and detonate a grenade ... muahahahaha.

Time to 'invent' more grenade/mine types for Shadowrun.  BL23C, here I come again.  The real trick lies in finding a cost-effective way to make them, you know?

[Mirikon]

Why hasn't anyone mentioned Lethal Weapon 2 yet? Bomb behind the toilet on a pressure switch.

Also, if they smoke, then switching their lighter for an identical copy filled with explosives rather than lighter fluid will be enough to ruin their whole day when they go to light up.

[The Wyrm Ouroboros]

Bugs Bunny for the win.