No, they don't make you sing and dance.
If you look back on past threads, there are many which detail the assessment day from start to end.
During the group exercise, we had to split into 2 groups where we had to do a radio appeal on whatever subject we wanted.
During this, if you choose to sing and dance then thats down to what the group decides to do in their appeal.
They are just looking for relevant skills, having an input but without taking over and listening and responding well to other peoples ideas & working as a team.
Hope this helps.
Just be yourself, thats the best thing you can do!
Good Luck!