This happened to me 2 days ago and has happened in the past. It usually happens when the temp get into the high 80s and above. All I do is what everyone here has suggested, I press load cd and take another cd to push the stuck cd back in. It may take a couple of tries but it usually goes back in for me. Once the car seems to be a bit cooled off with air conditioning, the cd then comes out without problem. Something must be expanding (cd, inside, who knows?) to cause the cds to get stuck.
2003 Tropic Green Metallic 3.8L V6: MGW Interior Billet Accessories (knobs and pony shift), Bullitt Fuel Door, Silver Bullitt Rims w/245/45-17.