Create a fast compiled method invoker using LINQ

var method = new Func<double, double, double>(Math.Pow).Method;
var parameter = Expression.Parameter(typeof(object[]));
var args = method.GetParameters()
    .Select((param, i) => Expression.Convert(
        Expression.ArrayIndex(parameter, Expression.Constant(i)), param.ParameterType));
var expr = Expression.Lambda<Func<object[], object>>(
    Expression.Convert(Expression.Call(method, args), typeof(object)), parameter);
var invoker = expr.Compile();
var result = invoker(new object[] {Math.PI, 2.0});

Create a Google calendar event in an existing calendar

var credentials = new GDataCredentials(userName, password);
var service = new CalendarService(null) {Credentials = credentials};
var query = new CalendarQuery("https://www.google.com/calendar/feeds/default/owncalendars/full");
var feed = service.Query(query);
var eventFeedLink = feed.Entries.Cast<CalendarEntry>()
    .Where(item => item.Title.Text == calendarName)
    .SelectMany(item => item.Links)
    .First(link => link.Rel == GDataParserNameTable.NSGCal + "#eventFeed");
var entry = new EventEntry(title) {Times = {new When(start, end, allDay)}};
service.Insert(new Uri(eventFeedLink.AbsoluteUri), entry);

Google Data API .NET client library

Page through potentially large NHibernate criteria query results

public static IEnumerable<T> Enumerate<T>(this ICriteria criteria, int pageSize = 1000)
{
    var entityCount = CriteriaTransformer.TransformToRowCount(criteria).UniqueResult<int>();
    var pageCount = (int) Math.Ceiling(entityCount/(double) pageSize);
    criteria = CriteriaTransformer.Clone(criteria).SetMaxResults(pageSize);
    return Enumerable.Range(0, pageCount)
        .SelectMany(pageNum => criteria.SetFirstResult(pageNum*pageSize).List<T>());
}

NHibernate