I’ve been to one of this Hyper Japan Event in the past, and I had a good time trying Japanese food, sake tasting, viewing a Japanese idol signing on the stage etc.
You could try on Japanese kimono, and I thought it was fun to do that!
Hyper Japan organaiser asked me to post their message, here you see the info

 
7 Days to Go till HYPER JAPAN in 2014!!!!
Let’s write it down on your diary now!!!
As you may know, HYPER JAPAN is the largest Japanese cultural event in the UK. This year, it’s held from Friday the 25th till Sunday the 27th in July at Earls Court.
You can enjoy both modern and old Japanese culture all together. It’s anything but everything Japanese; Japanese food at EAT JAPAN, Game thingy at HYPER GAME&ANIME PARK, see Fashion at HYPER KAWAII and HYPER FRINGE MARKET; get things from Japan.  
I assume you would be more interested in those three things,
Sushi Awards: You may be interested in tasting unique sushi creations from some of the leading sushi chefs in the country. It’s a great chance for you to see how real professionals to make world-class sushi.
Sake Experience: It will give the opportunity to taste more than 20 diverse varieties of authentic Japanese sake, learning about the different temperatures and ways in which sake can be enjoyed.
Food & Drink Demonstrations: Japanese cooking and drink demonstrations will both entertain and educate, inspiring you to create your own Japan inspired culinary masterpieces. 
The event is good for a day out for families, couples and friends as well as on your own (No worries you can meet new people at HYPER JAPAN!). This event should not be missed!!!!

For further information and book a ticket, visit on http://hyperjapan.co.uk