I'm with TLH. I send kudoses when I feel it's appropriate to send them. I don't pick some arbitrary day to decide "oh today is Kudos day." If I have to wait for a specific day to send a Kudos to someone, I might forget who I was going to send it for and why. Or I might decide at that point, that I don't want to send it afterall.
In addition, if people ARE following the "send Kudos Sunday" thread and abiding by it, and I don't get a Kudos that week, I get a tiny little itch in my feelings place, that spot that is still on the playground in 3rd grade waiting for someone to pick me for their team, 4 minutes before recess is over. I don't like that spot, or that feeling.
Lastly, it feels contrived, when you pick an arbitrary day of the week. In fact, it IS contrived. It's the very definition of contrived.