Easy to make, unique, and will keep dear ol' Dad's fingers warm in winter and comfy in summer (you know how hot those steering wheels can get!)
You will need: Knifty Knitter flower loom, yarn needle, loom hook, scissors, Lion Brand Hometown USA yarn (I used San Diego Navy and Oakland Black. You can use whatever colors you want, maybe even the colors of Dad's favorite sports team) or any super bulky yarn.
First, using an antibacterial wipe or cloth, clean off the entire steering wheel and dry it with a paper towel. (If you get in the mood, why not shock the pants off Dad and vacuum the whole car?) Then, using a measuring tape, measure the circumference and width of the steering wheel (SW). The SW that I based my pattern on measures 4" wide x 47 3/4" around.

Next, cast on pegs 2-11 of the flower loom, using the e-wrap (stockinette) method. You will be knitting 1 over 2, so loosely wrap pegs 2-11 with yarn 3 times and knit off. The key word is wrap loosely, otherwise you will struggle with knitting off. Keep the yarn loose, and you can work faster. You will knit off for 190 rows, or 38", unless you are adding different colors, which may take you up to 3 hours, depending on how fast you knit and whether or not you added different colors. The cover will probably curl naturally, like mine did as I knit it:

Next, leaving about a 5" tail, snip the working yarn and bind off the loom using your threaded yarn needle. Using one hand to position the cover at the top of the SW, stretch the cover around the circumference of the SW until the ends meet. You want the cover to be snug to the SW, that's why you knit it shorter than the actual circumference of the SW. If it is still a bit loose, frog stitches from the bind off end. Once you reach the desired fit, sew the ends of the cover together and knot the two tails together (the tail from the working yarn and the tail from when you cast on). Stretch the cover over the SW and position so that colors are to your liking (if you knit with more than one color).
Next, cut an 18" piece of yarn, thread your yarn needle, and (starting at the bottom of the SW) sew the ends of the cover together, pulling the yarn tight as you work, so that the cover stretches tightly around the SW as it is sewn shut.
In areas where you cannot sew the covers together, thread the needle through the outer loops of the cover
until you can sew the two sides of the cover together again.
Depending on how fast you work, sewing the cover onto the SW will take 20-30 minutes. When you reach the bottom of the cover where you first started, knot the two yarn tails together and pull the tails through the inside of the cover, snipping off excess tails as needed. And you're done!
Dad will certainly be surprised, and it will make his car just that much easier to find when he parks in a crowded parking lot; probably no one else will have a knitted SW cover!
If you make it, I'd love to see how yours turned out!