I filmed event where "creative" designer used cheap led lights to illuminate the ballroom (hundreds of them) which produced incredible flickering. I tried to use anti flicker filter in my Sony EX1 but it didn't help.
Is there any way I can reduce or minimize flickering in post production. I am using Vegas 10. Thanks in advance for any suggestions.

That sounds like a headache. Virtual Dub has a plugin called MSU Deflicker that has worked on some minor flicker issues in the past. It's free. Good luck.