What excites your students? Music? Movies or acting? Food?
 
If music:
How about breaking the kids up in small groups or 'rock bands', in which they come up with an English name for their band and a short description of the type of music they 'perform'. Without forcing real musical performances, arrange for each 'band' to be interviewed in English by other students pretending to be journalists from Rolling Stone or some other magazine -- like a press conference.  
 
If movies or acting:
How about having the kids perform an English-language play in class? Same concept as above: have other students be audience and others pretend to be journalists who interview the actors afterward. You could even add in an awards show where the performers give acceptance speeches in English too.
 
Or, if acting is too scary for your students, how about screening an (educational) English language film in class and then afterward have a student panel discuss and rate the movie in English (like professional movie reviewers)?  
 
If food:
Turn your classroom into a 'restaurant' or cafe and have the students order from an English language menu. Have them discuss items on the menu among other students at their table, just as they would in a real restaurant. Perhaps even bring in real food dishes to set the mood and motivate participation. If real food is involved, have them discuss it's smell, taste, etc.  
 
In all of the above: seek volunteers, don't expect their English to be perfect, and help the students along as much as needed, including using their native language to provide context or guidance as needed. Be sure to celebrate or reward the progress that is made too.
 
Below are some additional resources you may also find useful. Good luck!