I am trying to remember a cartoon from the late 70's to 80's. There were a few characters, maybe teenagers, maybe not, who would always be sent to another place and/or time. They may have time traveled, or just have been sent in some kind of machine or zapped to a place where their adventure or mission began. By the end of the cartoon, they would wind up back where they came from. I kind of feel like characters from other cartoons would appear in it but I could be wrong. Any recollections??