I think my dog had a seizure?

I don't know what happened. He was just running around playing...and all of the sudden he was like spasming,...he didnt whine or bark..no drool or anything....he was not tender to the touch. he looked like his back was out of place...but i felt all the way down his spine, and back legs, nothing felt odd. it lasted for about 2 minutes. he just kept bending his back legs and wobbling. After trying to see if something was broken or dislocated i just held him for a minute and when i put him back down, to go get my keys to take him to the vet he was back to normal...do you think it was a seizure...and what causes these and what should I do?