HAW! this is fun! and painful! My god, I remember almost all of them mentioned so far and am filled with the disturbing urge to learn them and inflict them on innocent friends--AH-HAA-HA-HA-HA!
I'd like to second "Chirpy-chirpy Cheep-cheep" I remember thinking that song was stupid when I was about 8 years old, and it's held up very well. Also, in the sub-category of Actually Offensive stupid pop songs, I'd like to nominate "Black Betty", by the mercifully defunct Ram Jam, from some time in the late 70's.
something like: [drums-n-bass] oh-oh black betty, blam-ba-lam, she's always ready, blam-ba-lam (no, really, i'm not kidding) born in birmingham, blam-ba-lam, way down in Alabam', blam-ba-lam oh-oh black betty! [catchy distorted guitar riff] black betty had a child, blam-ba-lam th' damn thing gone wild, blam-ba-lam gone out of her mind, blam-ba-lam, the damn thing gone blind, blam-ba lam oh-oh black betty! [more metal riffage] etc, etc.