Nostalgic TV shows you may have forgotten about

The Pirates of Dark Water, aired from 1991-1993 on the WB.
" The alien world of Mer is being devoured by an evil substance known as Dark Water. Only Ren, a young and handsome prince, can stop it by finding the lost Thirteen Treasures of Rule. His loyal crew of misfits that help in his journey are an ecomancer (Tula), a monkey-bird (Niddler), and a treasure-hungry pirate (Ioz). The evil pirate lord, Bloth, will stop at nothing to get the treasures for himself and provides many obstacles for Ren and his crew."It's one of those cartoons you might vaguely remember as a child, but no one else did, so you just assumed you made it up. Don't worry you're not crazy!

Space Cases, aired from 1996-1997 on Nickelodeon
No great wikipedia summary for this one. Basically it's a group of kids from different alien backgrounds who sneak onto an unknown space craft with their two teachers and get lost in space. It was THE SHIT, and had a the catchiest theme song. They had George Takai as a guest start among a bunch of Nickelodeon celebrities at the time.
And if the rainbow haired girl in the back looks familiar to you, that's because...

It's a young Kaylee from Firefly!!!

The Odyssey, aired from 1992-1994 on CBC.A young boy named Jay falls out of a tree-fort and ends up in a coma, and the show splits into two parallel worlds. The 'real' world where Jay is in a coma and is cared for by his mom and his friends on the outside, and the 'alternate' world where Jay is in another reality where adults don't exist. Basically once you turn 16 you just disappear from the world, and society is formed by children who have different clubs. Like the library club are kids who are teachers, the agriculture club are farmers, but they basically live in a police state where the oldest children form the most powerful club. Jay embarks on a journey to return to home reality with his two friends Donna and Keith (who also exist in the 'real' world as his best friend and his school bully, respectively).
This show is a TRIP. I used to watch it with my mom. Also, another fan favorite from the show:

Ryan Reynolds!