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.comfor signing up to do things, like bring food, take a class, collect payments, send reminders
regfox.comfor regestering for an event, including taking payments online sign-up sheets / time slot management online sign-up sheets / time slot management google forms online forms manage your mail lists manage your mail lists to coordinate meetings, to see who is available when? online voting (probably gone, server was unavailable from May through August, 2021)
I can no longer recommend this voting site. online voting invite sometone to an event

If you have additional sites you would like to see added here, please send me a quick note!