Whilst at university our tutors always spoke about doing things differently. Especially when entering a crowded market, you really need to stand out.
A business card can either be a run-of-the-mill throw away item or something rather original and memorable.
Often it is just a simple idea that really makes a difference.
Here are a few articles which show some really great ideas:
http://mashable.com/2011/07/23/business-card-designs/
http://www.artfans.info/20-original-and-quirky-business-card-designs/