My favorite Wild surges:
One time I was prepping for a big battle; while casting improved Invisibility on Keldorn I got a surge: Roll twice : Double hitpoints (on Keldorn, bringing him to over 250) + strengthened (strength upped to 23). That's probably one of my favorite surges that I've gotten.
Another time I was fighting in the beholder lair, Using my last nahals to try to cast a horrid wilting against a elder orb; I didn't get the wilting to come out, but I got: I feel refreshed. I then proceeded to cast a sunfire and kill it.
My funniest surges are all instances where I'm winning and I get "sex changed", or I'm about to kill a boss with a spell trigger and when I fire it, i get "wild surge: entangled". One Time I was fighting a mess of golems and I cast a project image, wild surge: area effect. My whole party was projected, it was sooo cool. Unfortunately, so were the golems