This week’s Big Bang Theory had Sheldon Cooper (Jim Parsons) up on a unicycle attempting to learn in order to keep his brain young.
Of course there were the standard unicycling is for clowns jokes and at one point he said that all cycles were stupid.
The odd part was that when on the unicycle his feet and the wheel moved quite a bit but the wheel went nowhere it just spun freely under him.
Here is the clip on Youtube
I’m sure it was just a television prop.
I thought so at first but if you look the rim and tire are spinning as he moves the pedals. It is just that the it isn’t going anywhere.
Could be up on a roller or something.
I see what you mean. It’s probably supported from the bottom so it can move a little, but can’t fall over, which is probably why it’s behind the sofa.
How strange. You don’t ever see the hub properly and certainly nothing below that - my betting is that the uni frame is bolted to a semi-rigid stand attached to the floor. Certainly all movement of the frame seems to be around some point about at floor level. I guess that makes it kind of look right, without it being something he can fall off - at least it requires very little support from the rope to stay on without any skill at all. With an unsupported uni he’d require at least some minimal skill to stay on even with the rope, I’d bet not many complete beginners could do that (I suspect holding onto a slackish rope like that would be kind of tricky even for those of us who can ride).
I agree, looks like the uni was in a stand that allowed the wheel to rotate, but didn’t go anywhere. Problem is, the show is watched by smart people! Tons of them will have noticed he wasn’t really “on” a unicycle, since it wasn’t moving. FAKE!
I can guess why they did it that way and didn’t let him actually be on it. That scene plays out very quickly in the finished program, but may have taken many takes to get it complete, during which his legs would totally wear out. With that low seat and low rope, his quads would have been toast in a couple of minutes. The stand kept that from being a factor (but also made it look fake).
They did a disservice to nerds everywhere by implying that they DO NOT do such skills (except for Wolowitz). If you’ve ever been to a unicycle or juggling convention, you have noticed that you are literally SURROUNDED by nerds and people who are really smart but not necessarily good at interpersonal relationships. Juggling attracts lots of mathematicians, I’ve noticed.
Even people with Asperger-like symptoms (like Sheldon Cooper) ride unicycles. I’ve met a lot of them. One was even involved in founding the IUF!
So what we know:
Jim Parsons does not ride unicycles, and also does not walk on stap-on stilts (I noticed there was something fake about his stiltwalking dream also). But Simon Helberg (Wolowitz) can juggle, though based on the brief amount we saw, I would guess he doesn’t juggle clubs. I woudn’t be surprised if he could ride the unicycle, but if he can, they wasted an opportunity there… 
Speaking of, I just spotted this article from last year:
Claude Shannon: Juggling Unicyclist Who Pedaled Us Into the Digital Age
Great article! I met him once. You’d never guess where – a juggling convention (IJA Festival 1983, Purchase, NY). You can search on his name in here to find my description of that event, and probably my lamentation that I didn’t try to take a picture of his cool “juggling machine” contraption.
I did know his name. It was on the cover of the Unicycling Society of America Newsletter, 4x per year, as one of the USA’s founding members. Only in 1982 did he get moved to the inside front cover, to make the covers prettier. 
Cool! Have you seen his scientific paper, “Scientific Aspect of Juggling”? I’ve looked for it before and hadn’t turned up a copy, but there it is now. I’m guessing that you might recognize some of the people and events he mentions.
No juggling or unicycling mentions in this one, but there’s a lot more about his work in this article from last month: “How Aristotle Created the Computer.” Alan Turing shows up there too, who never unicycled to the best of my knowledge but he bicycled a lot, like many in Britain in his time, and was also a world-class marathoner. He might have been a demon on a 36er in another era.
Quite a bit! I skimmed it; that’s a pretty hefty read! He was definitely a member of the IJA, and probably got a good amount of the historical stuff from their publications and/or archives.