I was at the Trans-Siberian Orchestra Beethoven's Last Night concert in Boston last night (in the fourth row of the orchestra pit) and it was awesome, they are quite the experience live, definitely worth seeing if you have the opportunity. They're so much more fun to watch and listen to than anyone else I've seen; their music is just so big (the benefit of having a string section and 20ish performers).
Just so you get the idea what it was like a found a few videos from other concerts in the tour on YouTube:
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