Ideas	Voting results and bounty paid	Comments

As simple as that, just tell all your friends, have them tell all of theirs, and in less time than you know, you'll have lots of people around looking for challenges on the site. I for one, already registered and got a couple of friends interested in it. So, the best advertising is good communication. Communicate away :)
Suggested by José

Get your friends, family, and associates to spread the word using social media such as Facebook and Twitter and traditional physical networking like cheap seminars and/or conventions
Suggested by Lamar

all over their bodies. get them to go to football games and fire-man's balls.
Suggested by hyuma

Send runners to every pet shop in the city that sells voice-mimicking birds and get them to train the birds to shout out your website and slogan Dang. This one's totally budget and brilliant too.
Suggested by hyuma

On 1's, 5's, 50's C-notes. Everything. Just change a whole bunch of cash and put the cash through a printer and imprint your address on it. Brilliant. Heck. I'm going to use this idea.
Suggested by hyuma

Ok, it's not the most proffessional method of advertising but, what can I say? it works. You'll get guaranteed visits from people and it's not expensive at all. Sites like NeoBux (the most proffessional I know of) will post your ads to people for a small amount of money per click and it'll get around really fast.
Suggested by José

One of the things I've seen work best besides from the common facebook/blogging things, is the common practice of flyer posting. You could have a promotion or something at the website, where an user gets a small amount of money for posting X flyers in his community (and providing evidence of doing so)
Suggested by José

You need to highlight a success on your site that "invites" folks to offer up problems to fix. If they think things don't get done, then why try.
Suggested by John

If you are truly crowdsourcing, it will be beneficial in many ways.
Suggested by John

Make sure your staffers contribute to other related blogs and comments on their blogs and other postings to get your name out there. Many people create buzz and crosslinking by contributing to other initiatives.
Suggested by John

send a simple, but informative one page press release (email, mail, get creative on the cheap) to anyone you can think of, friends, family, popular industry blogs, newspapers, review sites, old colleagues, etc. and hopefully out of that will come some FREE PR. at the very least it will get the word out, get people talking and ideally result in some written up articles/reviews. as long as you send something out you will be surprised at the response you will get.
Suggested by Troy

what does the gd stand for? is it part of the name? creative guide directory? creative global distribution? creative global drive? I'd buy more domains with a similar name/logos then track which one has a better response. That's another thing, what kind of submission review options are there? An ad campaign in business magazines, design websites, newspapers, would be basic targets. Specific websites when the budgets/reputation are better. Possibly contacting a design college & working with a teacher to make a contest for a reputable company. The prize money could be for tuition/scholarship money which is easier to raise.
Suggested by Anthony

Not a Facebook Profile. Not a Facebook Group. A Facebook Page. It's free, viral and worldwide. Use it like Twitter but it comes with other features to take advantage of. This is a must!
Suggested by Troy

Free, Viral & Worldwide! Promote new projects, announce winners, offer coupons, engage with people, ask questions. http://twitter.com/creativegd
Suggested by Troy

Expand your idea, and provide design work for page users. Find some sites, that need update or new site. Designer, who makes best design, is rewarded or get's a contract with the site that he has been working on. Moreover, make drawing for best design in current month. Take all designs, and ask people to vote. Best designer gets his hall of fame (special sub page, where he can show all his designs ...) Maybe you can make a special area on the first page "designer of the day" .. you will motivate designer to compete and provide even better designs.
Suggested by AnzeT'o

Find some good sized non-profits that need a better logo or some other design work. Put up the money for them yourself (might be tax deductible) - then promote it on forums that artists use. "Help this non-profit, we're supplying the prize." Might even get some press.
Suggested by Eric

Start a storm and mention your website for free advertising. Oh, you done that already :-)
Suggested by Baris