Just because I've seen every SpongeBob ever, multiple times, and I still find many of them funny, here's my TOP TEN FAVORITE SPONGEBOB EPISODES, in no particular order.
1. No Weenies Allowed - This is the one where SpongeBob tries to get into The Salty Spitoon, the toughest sailor's club, but is repeatedly kept out by the bouncer who suggests that he belongs at Super Weenie Hut Jr.'s.
2. One Krab's Trash - Kyle's favorite episode. This is the one where Mr. Krabs sells SpongeBob a beer drinking hat (which he calls a soda drinking hat) with a giant #1 on it, then discovers it's worth a million dollars and tries to get it back.
3. Shanghaied - The best of the Flying Dutchman episodes, it's the one where "Dutchy" gets SpongeBob and Patrick to be his ghostly crew and they're terrible at it.
4. Ripped Pants - I almost didn't include this because I've seen it so many times it almost nauseates me, but it's just such a classic.
5. Skill Crane - Squidward can't rest until he wins a stuffed animal from Mr. Krabs's crane machine, meanwhile SpongeBob wins over and over again, driving him nuts.
6. Rock Bottom - Patrick and SpongeBob end up on the wrong bus and travel to Rock Bottom, which is populated with weird monsters whose speech is peppered with childish spitting noises (their "accent").
7. Grandma's Kisses - SpongeBob is embarassed after everyone at the Krusty Krab sees him get a kiss from his Grandma and decides to be more adult. He doesn't last long, however, and at the end bursts out with a classic speech about wanting "a kissy wissy on his boo-boo" and a "sweater with love in the stitches!" I like to quote it to the boys when they're being whiny.
8. Club SpongeBob - Another classic episode for quoting; SpongeBob, Patrick and Squidward are stranded in the middle of nowhere with nothing but SpongeBob and Patrick's talking conch shell, which gives vague advice like a Magic 8 ball. Of course, SpongeBob and Patrick follow its advice and get everything they need which drives Squidward nuts.
9. Have You Seen This Snail? - Gary runs away and gets taken in by a kindly old Grandma who stuffs him with food. Sometimes I chase the boys around while quoting Grandma- "You don't want these to go to waste! They were a labor of love! You don't want cookies? I made a nice batch of deviled eggs!" etc.
10. Whale of a Birthday - Pearl wants the boy band Boys Who Cry to play for her birthday, but of course Mr. Krabs is too cheap to pony up the dough and hires Squidward instead.