As a chemist, I have acess to a lot of different chemicals. So here's a few cool things, and a mishap
This one is really fun if you ever get a chance: lake/pond + calcium/pottasium(large portion). The pottasium launched over 50 ft in the air, pretty cool
lots of dry ice and used 2 liter bottles (once one blew up too close to me and I had pieces of plastic in my arm)
Lastly, this one happened 3 days ago. I was trying to do a reaction, but it failed. Apparantly I had done something wrong b/c after a/b three hours of being in the trash can, the reaction started and caused a fire inside the trash can. When water didn't put the fire out, b/c it couldn't get rid of the reaction, I was forced to run the trash can outside and turn it upside-down in order to get rid of the oxygen to the fire. Needless to say, I got some wierd looks on my way out the door. My boss thought it was too funny and me too stupid and ashamed to really do anything besides tell me to be less of an idiot and more carefull.