THANK YOU to those who have already helped!
There are a few words for entertaining in Hebrew. There's מְבַדֵּר (meh-vah-DEHR), coming from the more common word, בִּדּוּר (bee-DOOR). There's מַצְחִיק (mahts-KHEEK), meaning funny. There's מְשַׁעְשֵׁע (meh-shah-ah-SHEH-ah), meaning amusing (I did an entry on משעשע this past January).
Here's a word that doesn't get used as often as the others... except for Purim. On Israeli radio today and tomorrow, it's likely that you'll hear the expression, פּוּרִים שָׂמֵחַ וּמְבַדֵּח (poo-REEM sah-MEH-ahkh oo-meh-vah-DEH-ahkh) - (Have a) happy and entertaining Purim.
Rumor has it that מבדח can also mean hilarious, but I can't say I've heard it used as such.
Anyway, פורים שמח ומבדח!