Ri Ra is located at the Mandalay Bay Place and sits next door to Las Vegas' first Guinness souvenir store (both opened in 2011). Ri Ra is a cozy Irish Pub that serves good food, beer, and custom cocktails. They also host, late night, live music. For breakfast, I like the Irish Benedict, for lunch & dinner, I like their Fish & Chips, Bangers & Mash, or an order of their Shepherd's Pie or Guinness Stew. They stay open until 3AM.
Vegas has quite a few good Irish Pubs (McMullens and the Nine Fine Irishmen are my other favorites) but I find myself coming back here often because I like the ambiance and location. The bar is beautiful and apparently shipped all the way from a pub in Ireland. Breakfast and lunch averages $16 a person and dinner averages around $22. Service is hit or miss (MOST of the time it is way too slow and they are almost always understaffed) but I've been pretty happy with the food.
I find Irish Pubs so comforting and cozy during the winter months. I'm not sure what their affiliation is to the Guinness store next to them, but they pour a really good Guinness beer here. They also have a lot of Guinness menu items such as Guinness stew and Guinness Sundaes.