It doesn't give a lot of energy or makes you want to move unless you keep the dose really low and try it in a social settings. On higher doses even if you wanted to move; you can't.
For me it feels serene, distant, surreal, wonderful, strange, weird, bizarre, absurdistic, confusing, deep;
It makes you body feel buzzing, numbed and tingling in a good way; your sense of dinstance and time are very messed up, vision becomes blurred, covered in static that can be colourful at times, especially with eyes closed and it might double up, it slows down and the number of frames slow down and you might see tracers. Not like a classical psychedelic but on higher doses definatly quite an intense effect. If you take a sufficient high dose your senses will be blocked off and you'll experience an inner world much like lucid dreaming (also on lower doses I can get the most amazing dark coloured but beautifully serene closed eye visuals of landscapes, people and I'll fly through those, all very surreal, in a dark room with eyes open and the right music everything can look so surreal and strange, wonderful), this is were people have the out of body stuff. You might also feel moving, tilting over, spinning but not in a dizzying way, especially with eyes closed you may not know what is up down, left, right, time, distance, future, past, meaning, reality, you, what it means to be human.
On a lower dose you just feel serene, comfortable, numb, strange and tingly though.
Personally, I love the feeling; ketamine is a dissociative so its not a downer or upper at all, somewhat of a psychedelic but not in the classical sense. It can give deep and meaningful psychedelic experiences but can also easily be taken casually or even in social settings in lower doses. A low to medium dose can be wonderful to dance on, you might not gain much energy but you won't be sleepy; it can keep you awake for a decent extra few hours if you redose often enough.
For a feeling of what it feels like; I wrote, created and sang a song about ketamine, and more people that did NOT know it was about ketamine said 'it sounds like ketamine', it might give an impression words could not.
http://soundcloud.com/azgaza/faceinthestatic Here's my ketamine song. Sorry for spamming my song
Also, look up trip reports on erowid, they can give a good indication (or read mine
I'm also azgaza on there; if you perform a search for azgaza + ketamine in the erowid trip reports vault you should find mine. Here's a link to erowid:
www.erowid.org
And read the ketamine topics, this tread may be merged or closed. Also bluelight has a nice search function and wikipedia isn't too useless either