Banana Cup
The cup after the Shell Cup is the Banana Cup. It's the second cup of the GBA Grand Prix. Its 4 courses include of a circuit, a lake, a land, and a castle. Its emblem is, quite obviously, a Banana Peel.
GBA Mario Circuit
It's another Mario Circuit! Like this wasn't expected. The main highlight here is the shortcut at the finish line. Other than that, it hasn't got much.
Like GBA Peach Circuit and other racetracks, GBA Mario Circuit changes with the seasons, so in spring it may rain and puddles may form, in summer it's neutral, in fall leaf piles may form, and in winter snowbanks may form. The sky, like most circuits, changes with the 3DS's internal clock.
Another Mario Circuit?! How many have we got now? 10?! That's a bit too many, don't you think? Anyways, this course doesn't have very sharp turns, and it's very boring. Oh, and it has a shortcut near the finish line too. --Lubba
GBA Boo Lake
This haunted, spooky track seems to be suspended mid-air above an endless abyss. Do you see the patched up spots and the purple trees? Spooky!
There is a 1/30 chance that Bomb Boos will litter the track! Hit one and it'll explode! Since it's dark and spooky, the sky doesn't change with the 3DS's internal clock.
Oh my! Look at those dead, purple trees! And that giant blue mansion! These candle-carrying Boos, the patched up spots, the many jumps, the branched paths! What a spooky track! --Lubba
GBA Cheese Land
Wha--? I don't get it! I can see the Earth from here! Are we on the moon? But, the moon isn't made of cheese! And Little Mousers don't live on the moon! What is this blasphemy?!
There is a 1/70 chance of Little Mousers appearing all throughout the track. Since there is no sky per se, this unexistent sky doesn't change with the 3DS's internal clock.
What is this place?! It's made of cheese! And I cna see the Earth from here! What are Little Mousers doing here anyways? Well, since this cheese is soft, the track can get pretty slippery. Be careful! --Lubba
GBA Bowser Castle 2
This track had recently appeared in Mario Kart DS. It's longer than GBA Bowser Castle 1, and it features more gaps and even trick jumps!
There is a 1/70 chance that all Thwomps get replaced by Super Thwomps, which are bigger and as such there is a higher chance of you getting flattened. Since it's indoors, the sky doesn't change with the 3DS's internal clock.
This is the second of the GBA Bowser Castles. Longer than the first one, it has many gaps and jumps. Careful of the trick jumps! --Lubba