In a nutshell:
The monkeys are back to put the Wii Remote though its pacing, with more puzzles, more features, more party games and, most importantly, more fun (and bananas).
They're monkeys, they're trapped in giant hamster balls and, unlike the recent Super Monkey Ball Adventure, they're super. This is Super Monkey Ball 3 in all but name, with the same mix of single player puzzles and party games as the original two games. As before the puzzle levels simply have you trying to navigate your monkey through a maze without falling off, except you don't control the ball itself but tilt the whole game world around it. The big difference now of course is that get to use the Wii Remote, which is perfect for the extremely subtle movements necessary for game. New features include a jump command (either the 'A' button or by actually flicking the controller upwards) and a number of boss battles that will test your monkey-in-a-ball controlling skills to the limit.
Most exciting moment:
As well as seeing the return of party game favourites such as Monkey Target and Monkey Race, Banana Blitz also features brand new concepts such as Monkey Fencing (where you jab into the screen with your remote) and Monkey Hurdles (where you have to pump the Remote up and down as if you were running). There are 50 party games in total and all use the Remote in a different way.
Since you ask:
Sega have said that all the characters from the previous games will make an appearance in the new game. There are also new ones planned too, including a female monkey named YaYa and a new simian scientist character.
The bottom line:
Super monkeys return to form in their biggest game yet.