An item that might be of interest to you 4th Edition D&D players:

Zone Effects – Flame (4)

For use with the current version of the world’s most popular RPG or many other games. Zone Effects are great for marking the area of a continuous effect or a sustained power. Scales up or down easily to mark larger or smaller zones and does not occupy squares on a battlemap. No more having to mark up the battlemap only to erase it when the effect is removed. Sold in a pack of four.

Here is the link directly to the item:

http://armorcast.com/store/product_info.php?cPath=116_110&products_id=1135