The marquee light up numbers are perfect as a decorative centerpiece for birthday parties. These 2 photos show a combination of letters and numbers setup for a 50th birthday party. These vintage style light up signs are easy to use - just plug them in. In this example, they are just sitting on a table and leaning against the wall but you can also hang them using a nail or even some string (they are very light). The numbers and letters are all 21 inches tall (roughly about 2 feet). They do need to be plugged in so you'll probably want to have a power strip available.
If you need to rent marquee letters / lights or, need uplight rentals - ProlightingRental.com is the place for you.