At the Gexcave, find the 4 glass panels. The one on the very right should contain a 1-up TV. Tailwhip the glass, then the TV. Eat the fly that comes out for the life. Then leave the room (try going to the training room) and return, and the TV will have come back!
Before you enter the level "Clueless in Seattle" there should be a snake head with a picture of DracuGex on the wall next to it. Look at it and you will turn into DracuGex! Jump and press "R" to fly but you will go down as you fly. Use DracuGex to uncover many secrets. Do not enter Lake Flaccid, Slappy Valley, or Funkytown or you will turn back into Gex. Don't enter any other levels either.