Ones that made me laugh particularly hard:
The League of Responsible Chemists.
Coffee and chocolate.
Genetic engineering homework.
Reviewing a scientific paper: Etiquette for reviewers.
These ones probably require some scientific knowledge:
Lunch through the mass spectrometer
Ligand substitution
Word plays and terrible puns:
Humpback
New Millennium
www.
And, eh, there's lots more there. So have a look if you're bored!