Can a person die of of taking a cocktail of pills? Like, just random pills they had laying around, not like 50 of each. ((Note: I'm not trying to kill myself. I'm just curious))

Absolutely. Each medication has a variety of chemicals. Some medications share the same ingredients which may cause an overdose if the combined amount is extreme. Also, the mixture of different chemicals may have severe reactions and may even cause death. There are medications that may be mixed with others,and some google searching may find results on which ones are safe.

But don't do it. What would be the point, and you have half a chance that it'll be dangerous. I'm all for experimenting, but be responsible ;)

I suggest you change your scope of curiosity to something much healthier and more productive.  You run the risk of a slow death from overdose as your liver begins to fail, an extremely painful death and one you cannot come back from if you wake and decide it was a bad decision made on a whim. In fact nearly all forms of suicide run the risk of a result much worse than death, ie prolonged suffering. Change your behaviour often your thoughts will follow. Arrange to meet up with a friend or family member.

Two of the students at my school died this way last year