Kaizo mario + mario maker so far, always gets the audience going.
I still think jump could do a segment, but I think only something like a 4way race would be watchable, races always been the most enjoyable to watch at ToTH. Less chances for a massive reset fest and a good dose of live competition. Could do a simple tournament scoring system over a handful of maps.
Downside is we'd need to organise 4 people to show (ideally people who could do both demo and soldier).