If you don't know the rules, here they are.
In the Red Corner: 10 robed Space Marines stand around mysteriously. One wields a flamer, and the sergeant is equipped with a massive power fist crackling with raw energy. (195 points)
In the Blue Corner: Evil, nasty, sadistic, drugged up Dark Eldar Wyches are bouncing off the walls ready for an arena fight - 15 of them in total. One wears a hydra gauntlet, and the Hekatrix wields an Agoniser and wears a strap-on Phastasm Grenade Launcher.
The Wyches roll for the effects of their combat drugs and get a 4 - they will be rerolling failed to-wound rolls throughout the bout. Due to their Fleetness the Wyches have the advantage to go first.
The gates open!
Bam! Despite the Wyches advantage, it is the Dark Angels who manage to get the assault, and to top it off the Wyches are caught out in the open! Shooting bolt pistols leads to 6 wounds on the fragile Eldar, and none are saved. We have a real battle here people!
The agile Wyches of course get to strike first. The basic Wych has two attacks, and the hydra gauntlets give d6+1. in total the squad gets 22 attacks, 3 of which are Agoniser attacks that wound on 4+ and ignore armour. The squad managed 14 hits including all the agonisers. Only 4 are converted to wounds, as they need a 5+, but don't forget that the Wyches can reroll any missed attacks...
The 10 failed wounds are rerolled and this time 7 of them wound - an incredible feat! Forced to allocate across the whole squad, at least the Dark Angels player can double 2 of the 3 Agoniser wounds on the same model. So two models die in agony, and another 4 from failed saves.
The Dark Angels hit back as best they can, but the Phantasm Grenade Launcher gives defensive grenades so they don't get any bonus attacks. 5 attacks deal two wounds - and both are saved by the Wyches 4+ invulnerable. The Marines run, are caught and lose another of their number to Fearless saves.
I'm afraid it's just mopping up from here folks. This time the Wyches only manage 6 wounds, including 2 from the Agoniser which are stacked on the fist. They however fail to save 2 of the remaining 4 wounds and are wiped from the table.
Aftermath: When the Dark Angels got the charge I held out a slim hope for them, but a combination of rerolls and good luck for the Wyches made this a non-contest. A very comfortable win for the Dark Eldar and I look forward to more of the same.