Rules:
Do not purposely jump off the island to regenerate your health.
Do not make a bridge to the mainland.
Do not use Mods, Hacks, Flying, etc.
Play on at least easy difficulty.
Do not make Nether Portal
Have FUN!

Challenges:

1) Build a Cobblestone generator.
2) Build a house.
3) Build Cobblestone Mob Grinder.
4) Build XP farm using Isle of Evil.
5) Connect all islands.
6) Make a meloon and pumpkin farm.
7) Make a sugarcane farm.
8) Make a wheat farm.
9) Make a mushroom farm.
10) Make an infinite water source.
11) Make a small lake for fishing.
12) Make something with redstone.
13) Make 10 cactus dye.
14) Make 10 bread.
15) Make 10 mushroom stew.
16) Craft 1 Iron armor set.
17) Craft 16 Glass panes.
18) Craft 12 Eyes of Ender.
19) Craft 30 Stone slabs.
20) Craft 5 signs.
21) Craft 40 ladders.
22) Craft 40 fences.
23) Craft 5 Fence gates.
24) Craft 10 trapdoors.
25) Craft 10 wooden pressure plates.
26) Craft 20 cobblestone stairs.
27) Craft 64 torches.
28) Craft 5 furnaces.
29) Craft a bed.
30) Craft 64 stone bricks.
31) Craft 10 Jack 'o' Lanterns.
32) Craft 10 bookcases.
33) Craft 2 wools each colour.
34) Craft 10 Paintings.
35) Collect 12 Ender pearls.
36) Collect 32 logs of each wood.
37) Collect 32 Gold ingot.
38) Collect 64 arrows and craft a bow.
39) Collect 64 bonemeal.
40) Kill Enderdragon.
41) Cook 15 fish.

Additional Notes

Next Update in 1.3 ;)