[gibybo]

I used "//" to get around the http regex (but this requires using an https host as you mentioned), is there another way to get around the regex?

[tautvidas]

Adding a space just before the URL works just as well.

[yen223]

Spoiler: RaNDoM cApS

[_august]

//www.google.com/jsapi?callback=alert

[gpvos]

data:,alert('hi')

[jonaspf]

Use upper-case characters

[vsakos]

i think ftp:// works too

EDIT: no, it doesn't :D