Ultimate Bravery is a fun gamemode where you get a random champion, itembuild and summoner spells.
The rules normally tell you, that you have to play with the displayed itembuild once clicked on the play button.
This gamemode became really popular after some well known youtubers where playing it.
Most of the Ultimate-Bravery websites are programmed once and never got updated, which means that you will see old items which can't be bougth any more.
If you are searching an up-to-date website, then you can follow this link: http://www.easy-lol.com/ultimate-bravery/