Yes, there is such widget.
I like this addon but I am finding two issues, hopefully somebody can help me resolve them.
1) Sharing: When you try to share an event on another page it does not work, you get an error (see below). The best you can do is share the event's thread but this defeats the purpose and forces me to make a thread for everything.
2) Invites: By default it is only letting me invite members one by one by searching their name. Is there anyway to mass invite, or even better to invite all members under a specific user group?
If these are not stock features, i would love to see them added in. I am going to keep playing with permissions in hopes to fix my first issue but the second one is more of a suggest upgrade. I'd also be willing to hire somebody to alter inviting to enable me to invite all members or a specific user group(s).