The Doris Baisley (Dramatists Play Service) version (which I have done twice), is a lot of fun. Has about 20 - 25 people and doable for HS and MS. It starts out as a troop of actors deciding to produce a play. The stage manager become Scrooge. You can go minimal or over the top! We built a raked stage on top of our stage (leaving the apron level) with a large box up center. The actors (a motley crew to be sure) poured out of the box, changed into their character for the play right on stage, and at the end, went back in the box! The box doubled as scrooge's bed (we added four poles as bedposts, when needed). For the ghost flying, we had a 2 sided ladder painted black which Scrooge climbed up (the ghost above him on the other side), and on a black stage (follow spot on ghost and scrooge), the stage crew, dressed in black, pulled the ladder (on wheels) around the apron. It was an amazing "flying" effect, getting us to the next location.
The show features a bell choir (ask a local church to help with this - or your music department) and it works well to ring in the season. You can add in songs too, during the Fezziwig scene. I really had fun with this script and so did my students. Lots of learning going on! Good luck with your decision.
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Ron Wells
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