There are advantages and disadvantages to any custom written software. The advantages are that it does exactly what you want, or at least it does after you have customized it to your liking. The disadvantages are that you need someone to install and maintain it.
There are several sites on the internet that have been used successfully by various clubs, including Potomac, and Chesapeake that are available to the general public that might just suit your needs. None of them are mine, your mileage may vary.
signupgenius.com for signing up to do things, like bring food, take a class, collect payments, send reminders slottr.com online sign-up sheets / time slot management google.com/forms google forms wufoo.com online forms constantcontact.com manage your mail lists mailchimp.com manage your mail lists doodle.com to coordinate meetings, to see who is available when? ballotbin.com online voting electionrunner.com online voting evite.com invite sometone to an event
If you have additional sites you would like to see added here, please send me a quick note!