From the Internet:
The seven basic plots are:
1. overcoming the monster;
2. rags to riches;
3. the quest;
4. voyage and return;
5. comedy;
6. tragedy;
7. rebirth.
HOW did we ever survive without Google and the Internet?
.
Oh yeah, books. :o)
How about: Boy Meets Girl, Boy Loses Girl, Boy Gets Girl.
Pretty common theme, if I recall correctly. :)