Make a Perfect Fake Report Card

If you just got a terrible report card, read on to find out how to turn that piece of garbage into the best report card you've ever had!

Steps

Make sure you have a fairly good scanner. A bad one will scan it in at too low a quality. This is bad because your "fake" report card will not look like it's real.
Scan it in at the highest resolution possible.
Open the image of your report card in Microsoft paint twice. You will take numbers from one and put it on the other.
Move numbers to change grades. For example, if you have a 97 in English and a 55 in math, you use the select tool to copy the 9 and put it over the first 5. You now have a 95 in math!
Do this until you feel you've raised your grades enough.
Change print options to landscape and fit to 1 by 1 page.
Print it out, then you're done!

If there is a some sort of parent conference meeting after the day you received your report card, be careful not to let your parents go.
If you have the type of parents who often call or email teachers to check up on your progress, this may not be a good idea.
Clear the history on your computer if your parents use it as well as you.
Before you print your "perfect grades", make sure there are no flaws that are visible on the paper. (Such as staple marks, pencil writing, particles, etc.)
This will only change what your parents see. Your GPA will still take a hit.
Try not to raise your grades too much. If you were failing a class first semester and now have a 98 in it, your parents will think something's up.
If your grades wouldn't be on the straight an honor roll then don't make them
If your school gives out report cards every quarter or semester, remember that you will have to redo any changes when the next report card comes. This is if all of your old grades and teachers' comments show up with the new ones.
Make sure that your parents don't notice that the texture of the paper is different.
Odds are, you will get caught, so be prepared. This is only recommended in the most dire situations.