House Party - S2-E5
Continuity mistake: Kelly said her youngest brother can burp his whole name Kenneth Leonard Kapowski in one burp. However in the previous year, Kelly had an infant brother named Billy. According to this info, unlikely Kenneth would be younger than Billy.
Suggested correction: Kelly can have more than one brother because in the episode where Kelly gets her job at the Max she said "I cook every night for my 11 siblings". So he could be younger or just have a nickname.
The mistake is valid because she says her "youngest" brother, not "younger." In the episode "The Babysitters" (which was meant to air in season 1 and produced before "House Party"), her brother Billy is an infant and says his first words. Kelly has 6 siblings and she never said she cooked for 11 siblings when getting a job at The Max. She says she sets the dinner table for 9 people three times a night.
Ironically, the show only reveals 5 siblings each in their own individual episode. (#6 is unknown). Bennett (mentioned), Nicki (seen), Kyle (voice heard only), Kenneth (mentioned), Billy (seen) are the 5 of 6 siblings revealed.
House Party - S2-E5
Continuity mistake: In this episode, Screech's mother kisses her Elvis statue before her trip while it is facing towards the right; indicating that this is the correct way that is should be facing. However, when she comes home after her trip the "new" statue is facing the same direction; right. She complains and says that the statue should always face towards the kitchen so he can see her cook; which is towards the left.