Today only, February 5, 2011, Groupon is offering a $100 Timbuk2 custom bag credit for $50 for a limited time. This voucher is valid online for custom bags only and expires on June 30, 2011. Limit one per person. Deal expires February 5, 2011.

Timbuk2 constructs each product from durable goods and provides a quality guarantee on each item. Designed to bear weight and stay in place, these bags are ideal for urban cyclists and wilderness adventurers alike. Much like text messages, customized orders can be delivered to your front door, place of business, or non-regulated submarine hatch.

Note: this is listed under Groupon New York City, it can be purchased and used by anyone.