My son threw a golf ball at our Sanyo LCD - 42" -
I assume you meant the screen is now broken.
Some things to consider:
1. Replace the son with one who does not throw golf balls in the house. Ha ha! [jk]
2. Check to see if the warranty (usually online if you don't have the original paperwork) covers screen breakage, or ask the store where you bought the tv if there is anything they can do.
3. If the warranty is a no-go, contact the tv manufacturer and see why they may do... what the cost would be to repair etc. Some screens are covered in case they crack, but it is probably obvious it wasn't a manufacturer's defect if a golf ball hit it.
4. If those steps don't work out, check videos or info online to see if this is a job you or a techie could do - (in last case scenario).
5. If none of these check out, sadly, you might be left with a very large, expensive doorstop.