Maniac Tunnel
The Ruin Maniac Cave is a cave south of Veilstone City. At first you will find a Ruin Maniac talking about Unown and a tunnel he is digging. He sets out a contest with you. When you go to the Solaceon Ruens east of Solaceon Town, you will find a few chambers there. In every chamber certain Unown can be found. In the six chambers you must follow to get to 'the treasure', you will find the Unown representing the characters F R I E N D (one in each chamber). The other twenty characters of the alphabet are found in the other chambers. You should visit them all, because some Unown only seem to appear in certain chambers. Besides that, you will find some small treasures in the rocks in some chambers.
When you saw all twenty-six Unown (you don't have to capture them), go back to the Ruin Maniac Cave. You will see that the cave is now called Maniac Tunnel and is in fact a tunnel. When you try to get to the end, you will encounter some Hippopotas and a lot Geodudes. At the end of the tunnel, the Ruin Manic tells you something, which is not important. The most important thing is, that when you go to the next chamber, you will encounter two new Unown, a question mark and an exclamation mark. Your job is done here now..