Super Mario Kart

By far the most popular racing game offered by Nintendo, the first game in the series (called, simply, Super Mario Kart) was released for the Super Nintendo in 1992 (1993 in Europe), and became the third best selling SNES game of all time. All games in the series that followed it have offered similar gameplay, while offering improved graphics and additional options. This was the first Mario game to branch off from platforming, and let to a variety of other experimental game designs.

In 1996, kart racing came to the N64 with the surprisingly-named Mario Kart 64; game boy players got in on the fun with 2001's Mario Kart: Super Circuit, followed in 2003 by the Gamecube's Mart Kart: Double Dash. Mario Kart DS released in 2005 (bet you can't guess what system it was for!), and 2005 and 2007 also saw several arcade versions were released,  
In 2008 game the latest version of the series (as of this writing), Super Mario Kart Wii; next year yet another version should be out on the new Nintendo 3DS.

The first non-arcade Mario game to offer more options than just the standard controller, Mario Kart Wii comes packaged with a Wii Wheel, and of course more wheels can be purchased inexpensively. The extra control offered by the Wii tilt and motion sensors make this the best Mario Kart game yet.

There are a number of characters available, including baby versions of several characters and even a few hidden options. As usual, the Wii limits you to four players at a time on any one system (this is a limitation of the hardware), but online play allows up to twelve players to compete on the same track.

I recommend always using the Wii Wheel (or similar third party wheels) when playing this game, as it looses a lot if you just use the controller! 

As usual, there's a quick start option: hit the gas when the 2 starts to disappear (but before it's completely gone) at the start of the race.

When you fall off the track, hit the gas as soon as you hit the track again and you'll get a quick boost. 

While there are plenty of characters available from the start, quite a few more become available as you win the assorted cups. Here's what you can look forward to:

Baby Daisy – Get at least one star rank for all 50cc Wii Grand Prix Cups
Baby Luigi – Unlock 8 Expert Staff Ghost Data in Time Trials
Birdo – Play Time Trials on 16 different courses/Get 250 wins online
Bowser Jr. – Get at least one Star Rank for all 100cc Retro Grand Prix Cups
Daisy – Win 150cc Special Cup or play 2,850 races
Diddy Kong – Win all 50cc Cups or play 450 races
Dry Bones – Win 100cc Leaf Cup or play 1,050 races
Dry Bowser – Get at least one Star Rank for all 150cc Wii Grand Prix Cups or play 4,350 races
Funky Kong – Unlock 4 Expert Staff Ghost Data in Time Trials or play 2,250 races
King Boo – Win 50cc Star Cup or play 750 races
Mii (Outfit A) – Win 100cc Special Cup or play 1,050 races
Mii (Outfit B) – Unlock 32 Expert Staff Ghost Data in Time Trials or play 5,100 races
Rosalina - Get at least one Star rank for all Mirror Grand Prix Cups, or play 4,950 races; if you have a Super Mario Galaxy save on the Wii, you only need to win a series of Grant Prix Cups or play 50 races
Toadette – Play Time Trials on all 32 different courses or play 3,150 races

Of course, new characters aren't the only unlockables; there are new karts and bikes as well!

Aero Glider (large kart) – Win all 150cc Retro Grand Prix Cups with 1 star or better
B-Dasher (medium kart) – Unlock 24 Expert Staff Ghost data
Blue Falcon (small kart) – Win Mirror Lightning Cup
Cheep Charger (small kart) – Get at least one Star Rank for all 50cc Retro Grand Prix Cups
Dragonetti (large kart) – Win 150cc Lightning Cup
Piranha Prowler (large kart) – Win 50cc Special Cup
Rally Romper (small kart) – Unlock 1 Expert Staff Ghost Data in Time Trials
Royal Racer (medium kart) – Win 150cc Leaf Cup
Turbo Blooper (medium kart) – Win 50cc Leaf Cup

Bubble Bike (small bike) – Win Mirror Leaf Cup
Dolphin Dasher (medium bike) – Win Mirror Star Cup
Magikruiser (small bike) – Play Time Trials on 8 different courses
Nitrocycle (medium bike) – Get at least one Star Rank for all 100cc Wii Grand Prix Cups
Phantom (large bike) – Win Mirror Special Cup
Quacker (small bike) – Win 150cc Star Cup
Rapide (medium bike) – Win 100cc Lightning Cup
Torpedo (large bike) – Unlock 12 Expert Staff Ghost Data in Time Trials
Twinkle Star (large bike) – Win 100cc Star Cup

What's all this about unlocking ghosts? If you beat the normal ghost for a course by at least seven seconds, you'll unlock an expert ghost to race against.