Curled corners of rugs can be so frustrating. Sometimes weighing them down with heavy objects or reverse-curling them doesn't put them back into their original flat form for too long. To remedy this, lightly dampen a towel and apply to the curled section. Set an iron on low heat and press down on the dampened towel where the rug is curled beneath. This should flatten the areas out. If it's severely curled, set iron to medium. Do not use too high a heat as you could damage the rug.
Don't do what my friend did. She got so frustrated with the ends curling up she nailed them to the floor.
That made me giggle! :)