RW-style "Out & Back" run on Elliptical (65 minutes at an effort faster than an 8:00 pace -- calling it 8 miles). Higher effort -- 147 bpm avg HR for 65 minutes (160 bpm max HR).
This machine is closest to XC skiing, imho. It allows you to adjust Stride Length to a max of 26.0 (inches, I think).
Stride length = 26, Level = 12, then 11. Tough, but high-end aerobic, not anaerobic. The legs felt much more like they were pushing off like a classic XC ski push-off.