Futurama! There might be some secret research in CIA, and Stan could go to the future and meet the Planet Express crew. Roger following him and meeting other aliens would be fun, too :)
AKATSUKI!!!!!!! it would be chaos. hilarious chaos.(if any1 from the american dad company reads this make sure theres plenty of akatsuki shots! no half american dad half akatsuki! ALL crossover! and do lots of research if you have to!)