Note: I have fulfilled all these challenges so don't excpect any thing like killing a gargauntar with a rake.
<c>Complete Last Stand with only 2 plantsHITORIDAKENO
Get a full zen garden
Complete Peking Express in under 11 seconds(my record is 10:25)
<c>Complete Last stand only using plants that cost less than 150 sun.HITORIDAKENO
Complete level 5-10 with one Jalapeno at the end.
Play wall-nut bowling without using lawnmowers.