It's been a funny kind of weekend - a mixed bag of glorious sunshine, World Cup defeat, and for those lucky enough to go, festival fun. And while we're usually a pretty cheery bunch here at 10:10, it has to be said that a few of us were feeling a little sluggish on the way into work this morning.

However, that was before we boarded the London Underground for our morning commute, and caught sight of these: three lovely 10:10 London Underground posters on the platforms and stairways of Earls Court, Charing Cross and Liverpool Street Tube stations. (You'll remember that ten stations signed up to 10:10 last month, and as well as cutting their emissions, are all proudly displaying the posters.)

Needless to say any Monday morning fug hanging over us was immediately lifted and we pretty much skipped the rest of the way to the 10:10 offices, more full of beans than a triple-shot latte.

Regulars amongst you will remember a few weeks back when the 10:10 logo was franked onto 36 million pieces of Royal Mail post. We asked you to send us pictures of yourselves posing with your 10:10ified mail - and rewarded the keenest 10:10ers with 10:10 tags.

Now, we're asking you to do the same with our fab Tube posters. Take a quick snap of yourself standing next to one, telling us where the station is (please remember, flash photography is forbidden on London Underground) and we'll send the first 20 of you a free 10:10 tag (alternatively you could just buy one here). Email your snaps, along with your name and address to hello@1010uk.org - and remember, we want to see your smiling faces with the posters!

If you want to go seek out a 10:10 Tube poster, you can find one at: Bank, Liverpool Street, Moorgate, Earls Court, Holborn, Charing Cross, Green Park, Knightsbridge, Hyde Park Corner and Victoria.