B717 returned to departure airport when the right engine failed for unknown reasons during climbout.

Narrative

Somewhere between 3;000 FT and 5;000 FT MSL at about 250 KIAS; we heard a loud bang almost identical to the sound the 717 simulator makes during an engine failure at V1 except much louder. We observed right-hand engine decreasing N1 and N2 RPM while TGT was in excess of redline (maximum observed was 1;150 degrees C). The aircraft did not yaw very much and not much trim was required. Stopped climb near 5;000 FT MSL. No fire warnings were noted. Only faults that we saw were 'TGT High' alert 2 and 'Bearing Overheat' alert 2. Performed immediate action item for Engine Severe Damage. I then declared an emergency requesting a return to ZZZ for landing with emergency vehicles standing by. When we were ready for the approach we were just north of the final approach course about 10 miles out. We told Approach we had ZZZ in sight and we were cleared for the visual approach Runway 33L. We were told to contact Tower. Outside the FAF I disconnect the autopilot and hand flew the approach. Landing was a non-event at flaps 25 degrees; deployed reversers/spoilers. At the end of the landing run; I PA'ed the cabin to 'Remain seated....' As we turned off at the normal point and stopped the aircraft; we switched to Ground and I established contact with the Fire Chief who was in an SUV in front of the airplane. I asked him to have his men inspect the right-hand engine for problems. The only defect noted was a blowout door open on the front of the eng cowling at the 6 o'clock position. The engine showed no evidence of fire or external damage.