Take 5 to 10 pieces of long strings to be hooked up above the walls across the room. Cut colored paper, preferably in different shades of green and yellow, in leafy shapes. Glue them in a row at equal distance along each string. Hook the leafy strings high enough on the walls so that none of them touches the head of even the tallest of your guests.
To make tent like shapes you can use your stools, vinyl chairs, coat stands, lamp stands. Then place large spread sheets and bed covers to cover each up in a tent like shape. Tape the four loose ends of the sheet with the floor to give the inclines of the sheet a taut look.
You can also hang masks of native Indians and masked heads of deer, turkeys, fowls along the walls of the room.
Place, if you like, potted plants, preferably the bushy variety, in the corners of the party room or hall and also along the corridor. Lay tablecloth with nature motifs or with prints of Turkeys and geared heads of native Indians. Place a customized Thanksgiving note below the placemats on each of the tables.
Ask your guests to say what they are thankful for. For a twist ask each one to add to their reasons what their predecessor's) said. You will be amazed to find how difficult it is to remember all of them at the end of one turn. The more the participants the more difficult it is to continue.
You can make it more interesting by asking the participants to scribble down the stuff on a pad. Serve each a pencil and a pad. It will be funny to note how words get changed.
Ask the children to go for a turkey hunt. Make one the hunter and get the child out of the room where a turkey, usually made up of paper, is kept hidden. For a better twist keep the hunter to be behind a closed door room. And ask the others each carrying a turkey to hide their turkeys at different parts of the house. Wait for a few minutes and when everyone's ready ask the hunter to start searching.
The paper turkey can be replaced by the kids themselves. Improvise the old hide-N-seek game to a 'Turkey hunt' by supplying a turkey mask to each of the children and asking each one to put it on their faces and hide themselves away in different places around the house.
Go As you Like: Ask the guests to join a go-as-you-like contest. In it each of the participants are required to take the guise of any character from the 1st thanksgiving feast by the Pilgrims and the Indian invitees. While some will sport the guise of a native Indian some will pose themselves as the Pilgrims. This will help recreate the ambience of the first feast.
If you have some more spare time before the dinner. Try this one out. Suggest that everyone write notes to family members and friends who couldn't be with you on this night telling them why you're grateful that they're a part of your life and that you're thinking of them. Have extra stationery, pens, and stamps so guests can join in. And if the writer allows, it can be read out.
It's best if you prepare ahead of time, asking the guests to bring CDs, tapes, or records of dance music of their choice. Allot each one a music from a special type so that there's not much duplication. Break out the Charleston, the Stroll, the Electric Slide, or the Macarena. Ask a member of each generation teaches the rest of the family a dance from his or her youth.