Tom Kane, Tom Kenny, Roger Jackson, and Jim Cummings all previously worked together in The Powerpuff Girls (1998) as the voices of Professor Utonium, The Mayor, Mojo Dojo, and Meat Fuzzy Lumpkins respectively, another animated series made by and aired on Cartoon Network.
You boys help yourselves to some delicious cookies. They got the chips and the nuts and the sugar and all that good stuff.
After Episode 13: Operation G.R.O.W.-U.P. alternate theme music played, and artwork from the show depicting the clubhouse being constructed is displayed.