Cheryl - One thing you can also consider beyond Phillip's good points...
You can add "up to date" content to nurturing emails using tokens. What I'm thinking is "Upcoming Events" or "Latest News" could be added as a Rich Text token at the top level nurturing folder. So what I mean is not on the individual nurturing programs themselves, but the top most folder you'd add a token, such as Upcoming Events. Then in your email templates you could create a section (a lot of templates have 2 columns / sidebars which I typically find get boring content.) and put in the token {{my.Upcoming Events}} ... If that token is in all of your nurturing emails, you will just have to update it once, in that top folder, then it will automatically be inhereted into all emails which contain it. Every week or few days as new things come up you can go back to that one token and update it so all your nurture emails contain relevant and up-to-date information. (Tip! If you format the token in rich text, you can only use it in one configuration. Format it in the template & you can use the token in several types of layouts)
Philip suggests adding webinars & events to the top of your stream. In general I support this idea. In practice working with other marketers to accomplish this, if invites are approved / finished late, or something obstructs a cast, it causes a lot of concern & panic. If you do add a webinar invite to the top of your stream, determine a "last date to send" and when adding the email to the stream, go ahead and schedule a batch campaign in the webinar's program. "Not sent email (Webinar Invite)" > run on "last date". This will not send to anyone who received it through the stream, but in case they hadn't gotten it through the engagement program it would ensure sure that they received it.