Sims 2: The Penguin
When you install the Sims 2 Seasons expansion packs, one of the random bits of silliness that comes with it is the penguin.
Typically, your Sims have only two actions for the penguin: greet, or shoo. Although occasionally your Sim will have the option to “talk to” the Penguin. I have only had this happen once, but it was pretty funny!
PENGUINS LIKE FISH
(Duh!) If your Sims are into fishing, you can take one of their catches out of their inventory and either set it on the floor, or mount it on the wall. The penguin will eat a fish which has been left on the floor. It will attempt to eat a fish which is mounted on the wall. It’s pretty funny to watch the penguin try to reach a fish mounted on the wall - it will hop up and down, and flap its little wings.
Some people have reported that if you feed the penguin a lot of fish, it will leave pee puddles all over your house. So keep that in mind, if you want to feed him.

PENGUINS ALSO LIKE SNOWMEN
If your Sims build a snowman, the penguin may stop by to chat with it. (This is of course a rather one-sided conversation.) My penguins spend a lot of time talking about crime. Apparently this is not uncommon.
PENGUINS NEVER STAY
Alas, the penguin soon decides it’s time to leave your lot. Several people have tried trapping the penguin by building a fence around him. After a set time, the penguin simply disappears.