Theobromine is a common component of coffee, tea, chocolate, and mate (pronounced MAH-teh). Particularly high in the last two.

Theobromine

            CH3
             |
             N
            / \
       N----C   C==O
      ||   ||   |
      ||   ||   |
      CH    C   N--H
        \  / \ /
         N    C
         |   ||
        CH3   O

Update: Being that mate is a spanish word, lordaych has informed me that it is actually pronounced "mah-TAY." For more info, go visit lordaych's excellent WU on the drink.