Website design with back-end calculations done regularly.

Essentially I want to design a website that is used to run a horse racing tipping competition. Currently I have 100 people in a competition that selects a horse from each race on a Saturday and the winning dividend of the horse race dictates the number of points that a participant who selected it receives. Essentially I need to come up with initially an extremely basic but usable design whereby the site has the ability for uses to log in and make a selection from a list of options. Upon the result of an outcome that the user will accumulate a varying amount of points and have a running tally reflected on a form of ladder or leader board. ITS MAINLY ABOUT GENERATING A WEBSITE WITH SOME BACK-END CALCULATIONS OCCURRING. Similar to a football tipping website that people can compete against each other. Each user will be able to see their previous week performances and their total score, average score and their ranking. On the website additional features would be: a register and login page facility a 'trainers' corner where communication between competitors would be like a public chat room. a running leader board, of the overall comp and each small comp they may choose to participate in. email reminder to each competitor if they asked for it In the future I may look to develop an application that would contain very similar features, with notifications rather than email. Similar websites would be: [login to view URL] [login to view URL] [login to view URL] Basis - customers to register for tipping comp - create their own username and password - enter selections for race meets, by selecting a horse out of a pre-uploaded field which changes each week. - links to odds/form guide possibly from an external source - possible payment to enter comp? Bpay/credit card - when races are run automatically update results from an external website and ladder is updated - lockout when race 1 jumps (nobody can enter tips after that time) this time will vary - sub activated (top weight - usually number 1) for those who forget to enter tips with a cap on its points if selected as sub. - room for advertising - most winners ladder plus much more Initially I would like the project to be completed quickly with the key element being the programming behind it rather than website aesthetics. I am working on a short time-frame, hopefully a working website completed within 10 days at the latest with further work to continue after that if required. I would need to update the website regularly with the names of the horses in races each week changing. If you had an understanding of horse racing that would be a great advantage... Looking forward to hearing all your responses.