Well, the round pen was dry enough this afternoon.... so why wait.
I walked into the round pen and he followed, knowing I had a bucket of feed. Once he got in, I locked the gate and put the feed outside. I pulled the rope out and he got nervous quick. He was so nervous that I tried to rope his front hoof - as suggested before (thanks cow pollinator). Once I got the lasso around his front right hoof he showed his strength, but I quickly walked around him and his back left leg wrapped in the rope as well. It was way better than I could have hoped for. After just a couple of minutes of struggling, he faced me and let me walk up to him and touch his neck (still while roped). I put a halter on him and treated a couple of small cuts he sustained in the fight. But once he realized I was in control with the rope, he calmed down really quick. He stood quitely while I attached a lead rope to his halter (no pulling at this time - just wanted him to see it). I wormed him, and brushed him for a while. Then on my terms I pulled the rope off his leg and let him loose. He didn't run around in the round pen as expected but was very calm. I went back and hour later and rewarded him with sweet feed and carrots. He'll stay in the round pen for a couple of weeks now while I work with him. Here's a pic of the colt after he was dead slap wore out, and just standing calmly for me while I brushed him and had just put the halter on. I never dreamed it would take less than an hour!