More from the bounty of Wikipedia: a list of all of the problems solved by MacGyver.
MacGyver creates a bomb to open a door using a gelatin cold capsule containing sodium metal, which he then places in a glass container filled with water. When the gelatin dissolves in the water, the sodium reacts violently with the water and causes an explosion which blows a hole in the wall. ("MythBusters" questioned the size of the explosion but verified that pure sodium does cause an exothermic reaction when mixed with water, just not enough to destroy a concrete wall.) The amount of sodium required to destroy a concrete wall would greatly exceed the size of a cold pill.
Despite the length of the page, the text warns that "this list is not yet comprehensive". (via gongblog)