My sister is a HUGE milkshake drinker and she almost always has one at Sci-Fi with her meal. It's a drink that you can have with your meal. However, I know they wouldn't deny you the milkshake you want for dessert either. I must say that the milkshakes are very, very tasty.
Also, they usually have a themed drink for the kids with those light-up ice cubes. When we've been there it was like a Lilo and Stitch drink. I think it was like a Shirley Temple with the cherry grenadine and sprite. They get to keep the cup and the neon light-up ice cube as well.
As far as the steak goes, I'm not sure. We usually have appetizers, salads, sandwiches- all of which are great!