Yes, those pictures really were from the graduation party we had with 
 our students' parents.  The photos really are self explanatory.  It was a
 fun filled night.  But I can honestly say I never finished a single glass of 
 beer that night.  hehe.  The parents kept coming by to refill our glasses 
 so often, I actually had to take drinks so they could top it off again.  
 This tradition of never letting someone else's glass get empty is a dirty 
 trick to thwart anyone who has decided not to get drunk for the evening.  
 Although I must admit, I am right up there with the rest of the Japanese 
 people as far as being a cheap drunk goes.  Not that I'd take my shirt
 off, but it wouldn't take much to get me on stage.  But the dancing
 to Shingo Mama was instigated by the hostess, and I don't think we
 had much choice in the matter.  Although, a certain male sensei, who will
 remain unnamed, probably had a choice about donning a stuffed bra and
 makeup, along with his wig and apron.

   In case your wondering, this particular occasion is by no means
 un-ordinary.  As a foreigner, new to the work scene in Japan, the 
 formal and stuffy atmosphere can be overwhelming at first.  
 But the after work drinking parties are one of most amusing surprises
 about Japan.  Even the most staid of businessmen will, after a couple
 beers, willingly tie his tie around his head and dance on the tables.  
 (I haven't gotten to witness this yet, but the dancing in drag was 
 just as good).  And not a stitch of embarrassment the next day.  
 Neither do there seem to be any qualms about what time of the day 
 you should or shouldn't drink.  If you have to have a party at noon,
 then by god, the drinkin' starts at noon!  I'm looking forward 
 to the cherry blossom festivals, when people camp out under the 
 trees and drink all day.  And all under the guise of enjoying nature's 
 beauty.  I know this because I saw them in Tokyo.  
 We went out well before noon, and already the little parties of 
 people in their business suits were parked for the day, giggling 
 and stumbling over each other, and, uh, marveling at the trees.

* Would you like to know more about this social phenomenon of drunk Japanese people?  Its quite simple really.  Its an interesting fact that how you act when you're drunk is a learned behavior.  Compared to Western societies, Japan is very formal.  There are very important rules to the social harmony here.  Speak evasively, don't stand out, don't excel beyond your peers, and always use complicated polite speech with superiors (all learned behaviors).  So there are also social rules that apply to drunk behavior as well (or an accepted lack of any rules as it seems to me).  
The Japanese system works so that most people work at the same company their whole lives.  'Drinking Parties' provide a way of establishing a bond among work groups, since under normal circumstances, it takes a really long time to get to know someone under the more formal, sober rules.  And you can't get anywhere in Japan if you're not part of a group.  Drinking has become the accepted mode of choice for escaping the strict social rules, (while still being part of the harmonious group, of course).  So go ahead, have a beer and don some rabbit ears.