Gifts that will blow a man's mind really depend on the man more than the gifts. You need to know a man's interests and get a gift that appeals to those interests. What's more, the gift should surprise him--it's hard to have your mind blown by something that you expect. There are some ideas you can start with and alter to fit the specific man you're thinking of.
One way to blow a man's mind is to get him a gift that directly caters to his interests and helps him pursue them. If, for example, he's a fisherman whose tackle box is always a mess, you could buy him a new tackle box. To make it mind blowing, organise it for him. Once he finds an organised tackle box ready to go, he'll be able to go fishing immediately.
You can also add a personal touch to a gift to make it mind blowing and ensure that he thinks of you each time he uses it. Have something monogrammed or engraved. If you know a man who is extremely style conscious, for example, a mind blowing gift might be a custom-made shirt that is made to his measurements and monogrammed with his initials.
You can also blow a man's mind by helping him make a memory. An excellent way to do this is to pay for a trip or outing for him. If he enjoys fine wine, for example, you could buy a ticket for a wine tasting tour. He'll get to taste a lot of different varieties of wine, he'll get out of the house for a day or a weekend, and he'll be able to spend time with you.