There are actually a large number of medieval sermons surviving, both in Latin and in various vernaculars, from across the medieval period, going back as far as Caesarius of Arles, who was active in modern-day southeastern France in the first half of the sixth century - around 250 of his sermons survive. There may even be earlier sermons, from the Early Christian/Late Antique period, but they're too far outside my wheelhouse to know about.

Whether the sermons we have surviving are actually what was read out in churches is a little more difficult to tell. Sermons were often preserved in collections, designed to be used as an educational tool by future preachers, and as such are more likely to be something like 'revised' or 'polished' versions, rather than verbatim transcripts of what a given preacher actually said. Even more unreliable are the sermons which were copied into chronicles and histories, often years after the supposed sermon took place (as is the case with Urban II's famous sermon at Clermont in 1095 calling for the 1st Crusade). However, in all cases, the sermons would have been recognizably a sermon and medieval people wouldn't have preserved it if they didn't think that it could be something which was delivered from a pulpit.

I'm not really sure what you mean when you ask for examples of sermons - there are thousands of sermons surviving from the middle ages and virtually all of them (for obvious reasons!) deal with aspects of the Bible. If you're looking for more information, however, you might want to check out the International Medieval Sermon Studies Society or their journal, Medieval Sermon Studies - although for the journal you'll likely need a university subscription to read articles, although T&F occasionally have some stuff on open access. If there's anything more specific you'd like to know about medieval sermons, I'll do my best to point you in the right direction!

Edit: Abstracts are free, actually, on the MSS T&F site, so that'll give you a good idea of the content if you want to browse the journal. To give you an idea of the scope, the most recent issue has discussions of sermons from the 13th, 14th and 15th centuries, from Italy, France, Germany and Sweden, with 60 volumes of back-issues too!

The surviving medieval English work which best reflects quotidian medieval preaching (and biblical exegesis) to the common people (or at least the laity) in the vernacular is I would argue, the Ormulum.

This is a difficult text for a number of reasons. First of all, because it uses an innovative spelling system largely of its own creation. Second, because the manuscript is quite a mess. Third, because, being a series of homiletic orations to be taken in regularly and sequentially but over an extended period of time, it is ill-served by immediate consumption en masse. It has consequently received little to no literary attention, over the years, and has been principally of interest from the point of view of historical linguistics and to a lesser extent ecclesiastical/exegetical history.

I cannot advise on translations to consult, though some exist, including that found at the Ormulum Project. Because this text is generally studied precisely for its text, and not for its literary or conceptual content (which has received characterisations along the lines of “drab homiletic pap”), translation has seldom been of any interest to scholars or literary figures. The text can also be found glossed in Fernand Mossé’s Handbook of Middle English, which is excellent, especially as a source for extracts from Middle English texts of lesser literary interest.