My sister and I went to the original venue held at the Fashion Show Mall parking lot, years ago- just wanted to show you how long I've known about it. We've gone a few times in the larger location- it's gotten huge (ie. packed crowd, so just a warning). The entrance fee has gone up, but you can get a four pack on www.lasvegashalfoff.com for $18. No outside food or coolers allowed.
Where else can you sample food from so many different restaurants at one time? It's like a super food court outside (but way better! most food courts don't impress me anymore, except Hawaii's Ala Moana) with live music (MIx 94.1 FM artists) and events scheduled- except the prices range from $1-$5 for smaller portions. One year, I got a humongous slice of Key Lime Pie for $1.00. The weather is just right at this time of year. The park, located on the west side, is such a nice one, that you can enjoy the grounds. It's a nice family thing to do. And the food choices are amazing. Make your rounds before deciding on what you really want or you'll be sorry.
We used to go to the San Gennaro Italian Festival but it's gotten pretty pricey for food and admission, that the whole thing cost us about $50 and this was a five years ago. This one's much better. Maybe, I can get my hubby to go this year. It's been a while. Food coma time.