Quote Originally Posted by Montmorency View Post
It is not funny to me. I don't get it.
None of the Bluths with the exception of George Michael can remember Ann's name. In the Year Book she is listed as "Not Pictured" under her photograph, although they did print a retraction in the spring supplement.[18][19] Michael refers to her variously (and always accidentally) as "Bland," "Egg," "Annabel," "Yam," "Plant," "Plain," and "Ann Hog." He once abandons her in Mexico accidentally.[21] Maeby takes pleasure in referring to Ann as "Bland".[22] George Michael tells Maeby that Ann is "not bland" when forced to defend his love interest.[22]
Basically it's a running joke about how bland she is, hence "Is she funny or something?" (ie not attractive).

AD is renowned for it's subtle humour and running jokes. See this: