I make a ton of stuff myself. However, that being said I don't second guess in the least my purchase of the Ultimate Sparge Arm from MoreBeer. Wait for it to go onto the daily deals and it gets down to about $100. VERY well made and on sale not a bad price for the high level of workmenship! http://www.morebeer.com/products/ultimate-sparge-arm.html Of course this is moot if you're doing a cooler style mash tun; type of mast tun to this point would be useful in conversation.
Try to find a cookie sheet a little smaller then your mash tun. Drill lots of little holes in it and put arms out from it to span your tun. I have a keeper on mine to hold the hose in place while I sparge. Good luck!
Depends on how fancy you want to get but I've seen some pretty cool stuff done with copper tubing and a hack saw. I fly sparge in a square cooler. I bent a copper tube to go back and forth over the top. I took the time to drill a bunch of little holes in the copper tube at slightly different angles so the water would spray evenly. Then I bent it and made a little bracket that would close in the lid and hold the copper tube up. That's my old way, I'm going to go with a modified keg here soon. I have the keg, just need the false bottom and get the hold drilled for the wort drain.
I have a 1/2" stainless tube coming in at the top of my mash tune. It's attached with a compression fitting, and is just a bit shorter than the id of the kettle. I crimped the other end and drilled holes on the lower half, and it works perfectly. This is in a 30 gallon kettle.
A round pizza pan could be used if you have a round mash tun. I've taken a decidedly simpler approach. I lay the hose from the HLT on top of the grain bed with about 2" water depth above the grain. This starts a gentle circular motion that seems, intuitively, if not actually, to result in a pretty even distribution of water without disturbing the bed. I find this to be waaaaay easier than batch sparging.
