Depends on the amount, but firstly some of the heaviest elements (the actinides wouldn't hang around for long, giving you a good dose of gamma radiation, some of the lanthanides would give you a nasty blast of alpha / beta radiation, bromine would make you cough very badly and would give you a very nasty burn if dropped on your skin, chlorine would destroy your lungs helium would make your voice squeaky. But in terms of spectacular reactions, well maybe the choline would give you some fairly spectacular clouds of Phosphorous penta chloride (choking stuff) but I don't reckon it would be that spectacular, now if we added water or a spark, things might be a little different.
Why on earth do you ask anyway ?