Songs currently stuck in your head

Umm Peanut Butter Jelly Time.
 
This one:
http://www.youtube.com/watch?v=1mEzemP7udo
 
Now also this one:
http://www.youtube.com/watch?v=IqmfaoCBfX0
 
Hip hip hooray for DNA!
It provides the key!


Yeah, we got shown this song as part of our undergraduate course.