The guys bonding with Alice's brother and showing him a good time, ending with them going to a pancake house at like 4 in the morning.
The episode where Blake, Anders and Adam are forced into drug addiction therapy. The whole sock puppet bit is heartwarming AND funny.
In 'Stop! Pajama Time' when "Adam" commits suicide and Ders (whose vision is seriously impaired at this point) freaks out and thinks his best friend has actually taken his own life can be taken as pretty heartwarming.
In 'Ders Comes in Handy,' when Adam is choking and dying due to an accidental hanging, Blake freaking out and yelling "My baby! My baby boy!" is a combination of hilarious and heartwarming.