The bizarre "spaceship keyboard" that Donna was forced to use is not a custom prop; it's an actual ergonomic keyboard manufactured by SafeType.
In the scene where Ben stands up to Leslie's Mom for whatever reason Amy Poehler couldn't keep a straight face and she only has one line in the scene, which took about 23 minutes to get right, you can view it on the season 3 blooper reel.
First appearance of Ethel Beavers.
Ann's full name is Ann Meredith Perkins.