Translating Japanese On A Souvenir Piece

I can ID the stamps BUT have no idea of what this item is about.
With luck someone here can help.
Sc# 2450/2499/2500

First image, top: 24th Sagamihara Cherry Blossom Festival
First image, bottom: (Postal code) 229 Sagamihara Post Office

Second image, top: Sagamihara Post Office Citizens' Festival Postmark Collection
Second image, bottom: [Cherry Blossom Festival commemorative postmarks from the eight previous years]

Third image, top: Commemorative postmarks
Third image, middle: [Three stamps with April 12, 1997 postmarks]
Third image, bottom:
Date: Heisei Year 9 [=1997], April 12th (Saturday) to 13th (Sunday)
Place: Sagamihara City Hall Cherry Blossom Festival

Some words are written differently in different places. Sagamihara, for example, is usually written in kanji, but it's written in hiragana in the red text on the cover. Sakura (cherry blossom) is written in kanji in the first image, but in hiragana in the third. Matsuri (festival) is written in hiragana in the first and second images, but in a mixture of kanji and hiragana in the third.