Toying with Elites
If you've got a single Elite to deal with (such as at the end of the rockslide megabattle, quite often), and you're in the mood for a bit of fun, here are some ideas, most of which involve establishing Human superiority in a way that should infuriate your foe.
Whacking and tagging
You could limit yourself to only using melee attacks, or only using plasma grenades. One evil thing I like to do is to provoke him into trying to whack me, then dodge and tag him close up with a plasma grenade as he passes; then stand back and watch. Or, tag him then jump over his head as he charges.
If he has a needler
If he has a needler, here are a few bits of fun you can have. (1) Dodge his needles for ages, perhaps occasionally moving in to whack him, just to let him know who's boss. (2) Armed with your own needler, kill him one needle at a time ('death by a thousand needles') whilst dodging his needles. (3) If you're happy to commit suicide, arrange for yourself go up in a pink explosion that also kills the Elite. You'll have to let yourself get weakened just right, before rushing in on a good stream of needles.
Continual backstep
Here's something else. Repeatedly backstep from a swiping Elite, and see how long you can keep him swiping at you like that. As long as your timing is good (and this should give you plenty of practice!), it looks to me like you can keep it going indefinitely. A good opportunity for this often comes at the end of a rockslide megabattle, when there's a lone Elite you have to go and deal with. Get in close to start him swiping at you. It may help if you get him into rage mode first.