OpenEuphoria

I'm not sure that we ever nailed down a license for the logo actually, but I can unequivocally state that you've got permission to do this.

4.3 Unaltered logos

Use of unaltered openEuphoria group-provided logos on T-shirts, mugs, etc.

• Again, non-commercial uses to promote the openEuphoria programming language are allowed. Commercial uses (which includes any use where you sell these items for money) require permission from openEuphoria group. Please reproduce our logos with the right colors and fonts; if you need help, let us know.
  
  
• Use of unaltered openEuphoria group-provided logos on websites, brochures, and product packaging - Non-commercial uses to promote the openEuphoria programming language are allowed, as are all nominative uses as described in section "3.3 Uses that never require approval", above. Any other commercial uses require prior written permission from the openEuphoria group.