I am sure you are all familiar with I Can Has Cheezburger, but this is a particularly fine example.
Those with a philosophical bent may enjoy the Ontologikewl Proof of Ceiling Cat:
Saentcat Anselm was liek Iz gotsa ideah of dis gr8test catbeing. Mai ideah of Ceiling Cat tis in mai miend. Ceiling Cat can bea realz. Srsly. Buttz ifs Ceiling Catz oenly plaeyin in mah hed and maibemietof existead den Ceiling Cat miet has bean moar pwnzor den he rlly is!! Oh noes!! Cuz den Ceiling Catz bigger in mah head den Ceiling Cat is fer realz! Airgoe, dis Ceiling Cat is moar grater den dat Ceiling Cat. Butz den, Saentcat Anselm was liek: "haha, I pwnzor uz catz wifout daeiteyz wif mah reduktshio add ubserdom!" Ceiling Cat can noe be bigger den anything else! Therefoars Ceiling Cat is in mah head ans in teh reelallities! Srsly!