My ds, 7 months old, is getting bored with his toys. He can't yet sit up by himself, so he can't easily enjoy some of the really fabulous stuff we have for him. He isn't too interested in the activity center that we have (it has a seat in which he sits comfortably). He enjoys the jumper thingie that hangs in the doorway for about 15 - 20 mins at a time. Any suggestions? He is quite energetic and I want to challenge and entertain him! Thanks in advance!