In all seriousness they need to completely get rid of that mug who does the PA at the games, he is extremely unlikeable and annoying. Do a crossbar challenge they are always fun. Talk to local charity or community projects on the pitch, supporter raffles things like that.
That "knock the Carabao cans over" thing would work better if it happened where a few more people could see it. Sticking in off the pitch alienates at least half the stadium . I think the raffle thing is covered, tbh. At least they make it clear what the winning ticket number is. I'm not sure I'd trust the club to do anything bigger after the Christmas fiasco. OMA makes a good point about the food / drink revenue. I'd also suggest that if the club added to what is currently provided at half-time, there's a very real risk that it would become the highlight of the day.
Best half time entertainment I've seen was at Southampton, it was a sort of obstacle course/race around the pitch two blokes and they had to race to score from the peno spot. Remember it being quite funny, that's about all im going to add to this thread.