I found these mildly amusing:
"My uncle is in a coma - he's living the dream" (Tomi Walamies)
"Have you heard they're doing a sequel to 'Brokeback Mountain'?" "No, what's it called?" "Brokeback Mountain 2" (David Wain)
I found these slightly amusing:
"Cellphones are like a dog's nipples. You don't have to shout into them!" (Emo Philips)
"My girlfriend said, 'I hate it when you finish my sentences.' So I said, 'Period' " (Sean Keane)