Len Valka Appointed Sales Manager for Houston Convention Center Posted by VenuesNow Staff | Jun 30, 2011 | Faces & Places George R. Brown Convention Center has hired Len Valka as Sales manager for specialty markets. To access this post, you must purchase Subscribe to VenuesNow – 1 Year, Subscribe to VenuesNow – 2 Years or Subscribe to VenuesNow – 3 Years. If you are already a member of VenuesNow, please login here: log in