As of right now, I believe you can only do this on the PBS Idea Channel. Here's me testing it out...

To do this, you click the share button and there is now a "GIF" option along with the "Embed" and "Email" options. When you click the "GIF" option, you can select a 6 second portion of the video and even add top and bottom text. You then click "CREATE GIF" and it gives you a URL and also an embed code so you can share your creation.

It's a very cool idea and I'm sure a lot of creative people on here will be able to make some awesome Ohio State gifs from highlights or full game videos.

Here's hoping they expand this to all of YouTube in the near future.