I had him come to my sons party last year. Bargain really, and considering he was flying out on holiday on the day and made a special effort to get to my sons party was a nice touch.
We had a football party so was quite easy for him, he went in goal for the penalty shootout the posed for pictures with all the kids. Not sure what he would do at anything other than a football party though. But it had the desired effect, son was over the moon and all his friends loved it.