Quite a few things, actually

. He likes to imitate the following:
*The front door opening, closing, and locking.
*Telephone
*Cell phone message alert sounds (usually beeps), and cell phone low battery sounds.
*Microwave
*Bodily functions, usually related to gas (not mine, BTW

). There's one particular relative he likes to imitate these sounds from

.
*My dog Maxwell howling. When he gets separation anxiety, he howls.
*The squealing pig on the Geico commercial, though he doesn't do it as much as he used to.
*Curly Howard's "N'yuk 'n'yuk n'yuk" followed by "woo woo woo"

. Sometimes I'll say "N'yuk n'yuk n'yuk!" and then he will go "Woo woo woo!".
*Phone conversations
Other things he likes to do:
*Yell at the dogs if they start barking or howling. He usually yells, "Hey, hey, hey! Stop it! Stop it! Maxwell! Pepper! Stop it! Hey, shut up!"
*When I get home from work at night (I usually work nights) around 1 AM, he whistles when I come in the door and then asks me, "Are we ready to go night-night?"
*He also likes to tell me to stop it if I get in a bad mood and start ranting around him, but if I tell him to stop it, he pauses and then says, "Alright."
*Anytime I leave the room, he asks, "Where's Anna?"
*A relative thought it would be funny to teach him the Batman theme, so now he likes to sing, "Doo doo doo doo doo doo doo doo doo doo doo doo doo doo doo Baaatman! Baaatman! Baaatman!"
*His favorite song so far is the disco song "Get Down Tonight". He skips over the "Make a little love" part, so all he sings is "Do a little daaance! Get dowwwwn! Get dowwwwn!"
That's all I can think of for now. He's an entertaining fethered pal to have around

.