There are many results on the Wild Magic sorcerer's Wild Magic Surge table (PHB, p. 103) that says "centered on yourself". For instance:
07–08: You cast fireball as a 3rd-level spell centered on yourself.
13–14: You cast confusion centered on yourself.
I'm not sure if that means that the spell originates from you as normal, or if the spell affects only yourself (that doesn't make much sense), if its cast as an area spell, or what exactly it means.