Sucky situation. Even when parents are stupid you just have to do your best to maintain a positive relationship with them. It's much the same with inlaws.
Here's my solution: Lie to them. Apply where you want to apply and where you will get in. Then make a fake html page that shows your school ranking in the top 25. Maybe not #1, because I good lie has to be believable.
Next, if they mention to somebody else that you are at a top 25 school and the person refutes them- launch into a tirade about how the othe person has no idea what they are talking about. Probably a good idea to save your fake html page because I visual aid could come in handy here. Try to play to your parents weaknesses by appealing to their sense of honor or just laughing off the other person as ignorant.
Finally, if this relationship-wrecking intruder seriously presses the not-top-25 issue with your parents, you have two drastic options: Kill the intruder or seriously injure yourself. In all honesty, killing the intruder will be a more permanent solution, but medical licensing could get tricky with a first degree felony. Plus, if more than one person brings the not-top-25 issue up to your parents this could get complicated. That's why I recommend option number two. The perfect serious injury will take everybody's minds away from whose what is in the top how many. And note that I said "injury" - you're going to want to make this one recoverable.
Okay- my real advice is to try and maintain an even keel. Getting too excited or too bummed about anything can cause excessive anxiety before the fat lady has sung. Be patient, rational, and understanding. Remember that you love them and that they love you and that there is almost always a compromise. Good luck.
PS- you might try to explain to them how silly those "rankings" can be. Find a reason to convince them that YOUR school is the best.