Looking for an "Olam Iruim" in Raanana, well there are plenty of great small event venues and restaurants that can be used for small events, but larger events normally have to be celebrated outside of Raanana. Well there are at least 2 event halls in Raanana which can cater for approximately 200-250 guests. Both are in the Raanana industrial area. The first is Migo, which was once called something else and before that it was the Hanger store. It is situated opposite the Mall (Kanion) at 15 HaTa'asia Road. From personal experience I can tell you the meat is about the best I've tasted at an Israeli events hall and they serve large helpings. They also have a deal where you can get the "design" (table decor, balloons etc), D.J. snacks for kids, sound and lighting for an all inclusive price. There is an upstairs area for kid's games during the event, and they have a resident D.J. you can choose to use or not. I know their average price but I'm probably not supposed to say, if you want more info leave me a comment and I'll get back to you.
The other events hall in Raanana is quite new, it is near the present location of Hanger at 10 HaTa'asia Road and is called Yoma Zoar and can be contacted at tel: 09-7466555. Sorry I don't know that much about it and couldn't find their website, but the adverts look good.