Awesome sight to see if you're out in Vegas! Seeing an erupting volcano on a hot summer night, was probably not the best idea! Anyhow...
I stayed at the Treasure island and I had a perfect view of the strip and the volcano. It was awesome seeing it erupt from afar but up close was a little overwhelming. Show starts promptly at 8pm so crowds start forming around the area around 7:30pm. If you want a good view you're going to have to get there pretty early. We got there right at 8, and it was 109 degrees outside, so trying to get to the front of the crowd wasn't going to happen for me-it was definitely all sorts of caliente that night!
Make sure not to stand too close to the railing as it can get pretty hot once show starts. Beware of the tourists too-people can get a little crazy and pretty rude at times...we all want that perfect picture for posting!
The show lasted a good 5/10 minutes and was worth checking out. My young cousins had a blast watching it (4-9 year olds). You can't beat free entertainment when in Vegas. And if you want to cool off walk in to the Mirage Hotel and Casino for that beautiful air conditioning!