This is one of the ones I loved watching when they showed it on reruns. Basically, Peggy decides that Seven deserves a birthday, but the only problem is, she has absolutely no clue when his birthday is! After listing two dates that turned out to be Kelly and Bud's birthdays, she finally comes up with one. The next day.
Al comes home, and when Peggy finds out it's his birthday she completely ignores him, taking away his day. Poor Al.
They go to the park, but find out some snooty rich family rented it out for THEIR son's birthday. The rich folk give the Bundy's a small section that isn't even considered good enough.
In the end, they do what Bundy's should do. Fight. Great way to end an episode, and shows that Al doesn't COMPLETELY hate his family.