Crate training - the easy way. Lead your dog to the crate and say "crate" (as the command) and toss a cookie in there.
Usually the dog will follow the cookie.
It worked wonders with Luna. She's very good with it now.
Pongo still needs bribery, though.
I've found out that at night a rawhide or a bone in there for them to chew on (something to do) can help - if you don't mind the chewing noise.
Be careful, though, Pongo has a bad habit of sucking anyhting he can get into the crate. It's amazing what'll fit though those tiny vent holes!!