artist

My friend has an on-going exhibit of his paintings in an art gallery in our town. His exhibit ran for a month and it has been very successful so far. July 12 is the last day of his exhibit and there will be a thank you party to celebrate the success of this venture. I know my friend really worked hard to make this a very successful exhibit and so I wanted to give him a gift to let him know how proud I am of him for this accomplishment. What kind of gift do you think would appeal to an artist like my friend, a male who is in his early thirties?