If you knit, here's a pattern that I found and have used myself. I don't make mine 3" like the instructions say. I just use ends of balls of yarn and stop when I get to the end.
http://www.frugalhaus.com/homepage/ponytail.htm
Here's the text from the above link:
Frugal Knitting Haus Free Pattern(s)
PONYTAIL SCRUNCHIES, RUFFLED, AND SUPER-RUFFLED - (see note below)
(Great quick and easy to make for party favors, stocking stuffers, etc. make a wardrobe of colors for the children!)
Materials: Sportweight yarn, or baby yarn, about 45 yards for ruffled, and about 60 yards for super-ruffled. 1 PR. U.S. # 4 needles. Elastic ponytail circular bands, one for each scrunchie made.
Gauge: 6 sts and 8 rows = 1 inch.
Note: If using baby yarn, the gauge may be slightly different, but only gives a slight difference in finished product.
Directions: With color of yarn desired, cast on 125 sts for ruffled, or 160 sts for super-ruffled. Work in stockinette st until about 3”, to 3 ?” in length from beg, or as desired. Bind off.
Sew lengthwise knitted piece all around entire circle of elastic ponytail band. Sew side seam..
Note: In above photo, yellow scrunchie was made “super-ruffled”, and about 3 inches long . Pink scrunchie was made as ruffled, and about 3 ? “ long. Make your own color combinations in stripes or colors as desired.
Copyright 2003, Frugal Knitting Haus, Harpers Ferry, WV 25425-0346