Recruiting Employees at Job Fairs

Have you found job fairs to be effective in recruiting new employees that fit your needs? Most job fairs are only open during regular working hours so it seems like you would only attract those people who have little or no experience and can’t seem to hold down a job. Is there a better solution for seeking employees who simply want to improve upon their current working situation? I think that if someone started a web site that connected employers seeking employees with particular skills, it would be a useful service no matter the location. It would be worth any fees paid by the employer in order to weed through prospective employees so that they could limit their interviews to those with the prerequisites they are looking for.