The name of
your page is:
Y qué es la felicidad%3F
Although, using Firefox and and an EN, UTF-8, MW v1.4, it seems to work fine
by just creating a link in a page with a question mark in its title or, if
you have the 'search' Go function set to open an edit page for pages not
found, it can simply be entered there. The question mark only seems to be
problematic if used directly in a URL, as would be expected.
It is stored in the cur table as just 'blah?'.
John Blumel