diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..d8c2032
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,2 @@
+[alias]
+xtask = "run --manifest-path ./xtask/Cargo.toml --"
diff --git a/README.md b/README.md
index 6b7a46c..c6799a9 100644
--- a/README.md
+++ b/README.md
@@ -107,8 +107,15 @@ to update `last_modified_on`. Some clients use `last_modified_on` to decide whet
 update to an event or recurrence or not. To ensure the client will publish the event, set
 `last_modified_on` to a value in the future (a few days past the current date should be enough).
 
-On Linux, you can get the current time in the right format in UTC with the command
-`TZ=UTC date -u +"%Y-%m-%dT%H:%M:%S.%2NZ"`.
+## How do I generate a UID for a new event?
+
+To generate a UID, run:
+
+```sh
+cargo xtask generate-uid
+```
+
+Use the printed value as the `uid` for the event.
 
 ## How do I remove an event?
 If the event isn't recurring, then you don't need to remove it, it'll just stay in the calendar
diff --git a/xtask/Cargo.lock b/xtask/Cargo.lock
new file mode 100644
index 0000000..5b5f481
--- /dev/null
+++ b/xtask/Cargo.lock
@@ -0,0 +1,39 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "calendar-xtask"
+version = "0.0.0"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "getrandom"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4567c8db10ae91089c99af84c68c38da3ec2f087c3f82960bcdbf3656b6f4d7"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.162"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18d287de67fe55fd7e1581fe933d965a5a9477b38e949cfa9f8574ef01506398"
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
new file mode 100644
index 0000000..0e43fc4
--- /dev/null
+++ b/xtask/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "calendar-xtask"
+version = "0.0.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+publish = false
+
+[dependencies]
+getrandom = { version = "0.2.15", default-features = false }
diff --git a/xtask/rustfmt.toml b/xtask/rustfmt.toml
new file mode 100644
index 0000000..2a35f02
--- /dev/null
+++ b/xtask/rustfmt.toml
@@ -0,0 +1 @@
+use_small_heuristics = "Max"
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
new file mode 100644
index 0000000..9178ad3
--- /dev/null
+++ b/xtask/src/main.rs
@@ -0,0 +1,50 @@
+use std::process::ExitCode;
+
+/// Generate a UID for an RFC 5545 iCalendar event.
+///
+/// The iCalender (IETF) RFC 5545 requires, in section 3.8.4.7, that
+/// the `UID` be a:
+///
+/// > ...persistent, globally unique identifier for the calendar
+/// > component.
+///
+/// In this context, "globally unique" means that the identifier must
+/// not collide with any other identifier for any other calendar event
+/// across all calendars, ever.
+///
+/// To achieve this, we'll generate a hexidecimal encoding of 160
+/// randomly-generated bits.
+fn print_uid() {
+    const UID_LEN: usize = 20;
+    let mut xs = [0u8; UID_LEN];
+    getrandom::getrandom(&mut xs).unwrap();
+    xs.iter().for_each(|x| print!("{x:02x}"));
+    println!();
+}
+
+fn print_usage() {
+    const USAGE: &str = "\
+Usage: cargo xtask [OPTIONS] COMMAND
+
+Commands:
+  generate-uid, uid    Generate an event UID
+
+Options:
+  -h                   Print help
+";
+    println!("{USAGE}");
+}
+
+fn main() -> ExitCode {
+    let mut args = std::env::args();
+    let _arg0 = args.next().unwrap();
+    match args.next() {
+        Some(x) if x == "-h" => print_usage(),
+        Some(x) if x == "generate-uid" || x == "uid" => print_uid(),
+        _ => {
+            print_usage();
+            return ExitCode::FAILURE;
+        }
+    }
+    ExitCode::SUCCESS
+}